0 works. if the hope is for them to be a reasonable partner for afghan allies, other members of former of the afghan government or the u.s., that one indication there. i'm jim sciutto. thank you for being with us. that is flick robertson with me there. "at this hour" will start now. >> this is cnn breaking news. >> hello, i'm kate bolduan. we're continuing this follow the major breaking news in afghanistan. there has been an explosion outside of kabul airport. officials also say this appears to be a suicide attack. let's be clear. this is still unfolding and there are many questions and things are still very fluid right now. we don't know who is behind the explosion. but the u.s. officials have been warning about a credible imminent and compelling, that is how they put it, threat from isis-k for days now. the u.s. embassy in kabul just 30 minutes ago issued a new warning to u.s. citizens near the airport. essentially the message is very clear. leave immediately. let's get to it. barbara starr is live at pentagon. barbara, what are you hearing right now? >> well just a few moments ago the pentagon confirmed there has been a second explosion. we don't know yet if any potential fatalities or wounded. either among u.s. personnel or afghans were there are a result of the first or second explosion. let me say separately, defense official with knowledge of the situation tells me that they are bracing for more and that is exactly what you would expect from the u.s. military in a situation like this. they will take all measures to protect themselves anticipating there could be more attacks. that is just common sense. there are some u.s. personnel injured in this attack. that is the only details we have at this point. the pentagon has not said where they are military and what branch and whether they may be state department or personnel working for other parts of the u.s. government. we know very much that there are u.s. families out there watching this, afghan families watching this who are going to be very concerned about their loved ones. also no claim of responsible just yet. that we are aware of. as you said, isis in afghanistan has been threatening an attack, the u.s. believes there has been very strong stream of intelligence sug-- suggesting t would conduct a suicide attack and they are the hallmark of any number of terrorist groups that operation in the region. so very early word about all of this. the pentagon, the defense department, the intelligence community, the white house trying to put all of the pieces together, to try to determine what has happened and trying to move very quickly to take care of those who may be injured, kate. >> and just as you were reporting and just as you're reporting we have a new statement from the pentagon press secretary john kirby. we could confirm that the explosion at the abby gate was the result of a complex attack that results in a number of u.s. and civilian kcasualties and we could confirm one or more explosions a short distance from abby gate. we'll continue to update. confirming what you were just reporting, barbara. >> right. there had been some very early word of multiple explosions. and complex attack. we don't know but this is often the beginning of the language you see from the u.s. government that sug a suicide vest potentially a car bomb, a sniper, these are the hallmarks of the groups for so many years. they stage the complex attacks, if you will, sometimes there are very tragically a first explosion that gets people running, and then they set off something else. that is kind of a hallmark of what happens. so i want to emphasize, we don't have the specific information here. but this kind of complex attack is exactly what has been worrying the biden administration for the last several days. and is exactly the reason that the u.s. forces at the airport, some 5,000 plus of them will very much be in a mode of protection for themselves and for each other doing whatever they can to protect the afghans on the airfield trying to continue flights if they can. not at all clear what the pace of activity may be. they still have, by their own calculations, a significant number of american citizens, passport holders, that they will try and bring in. they try and bring in any afghans if they are able to. but the priority now in these final days has been to bring americans into the gate, get them on flights and get them out of there and then very quickly the u.s. military has to shift to packing itself up and being ready to go. it is tuesday, just we're beginning to move from counting the days to counting the hours, aren't we, before the u.s. has to be packed up and gone. kate. >> barbara, with the latest breaking information now. a second explosion as confirmed from the pentagon press secretary. barbara, please stick close. nick paton walsh is live in doha qatar. you were talking about last hour that the second explosion according to the pentagon is at or near the baron hotel? >> this is essentially the same place. and so we are talking about as they said a complex attack. so not just two explosions. there are reports of gunfire. the order nair response to security guards hearing something like that. the abbey gates, this is the main gates over the past few days into which people limb itsed as they were have been trying to get into the airport. it has been often suecured by u.s. military personnel but outside there are intense crowds. i saw a video yesterday of a mix of u.s. and u.k. service men walking up and down razor war and below them were afghans on the bank holding up pieces of paper and proof they had to make their case, that they thought, that they should be allowed to be part of the siv program. and packed together and that increases in density. a very desperate people trying to get in. it is, i have to say, given what we're hearing about this, quite likely that a dense crowd like that may have been in fact the target. quite how u.s. personnel who we hear from the important were also injured too ended up into that is unclear. did an initial part of the attack draw them out, were they trying to assist people who were caught in the first explosion, and then another one came. we simply don't know at this stage. but certainly the scene there means certainly judging from some of the pictures you've been playing as well over the past half hour or so, we're dealing with a densely packed area, different casualties who could be behind this in afghanistan you can't count on a claim of responsibility. isis do step forward and say this was them and they're swosworn enemies of the taliban and al qaeda too. and many other extremist groups there too. so that is all i'm sure something they're working feverishly on now to see how sustained the threat may be. but the notion of a secondary explosion at the bar ron hotel will suggest a lit of culprits able to pull something like that off. the baron was where the british were based. they were reducing their presence if not departing today and of course the security risk to troops and situations like that is always during the withdraw phase, when they are able to defend themselves. we simply don't know if that played into this. but with this evacuation still hoping to go on at some pace, our understanding until the weekend, but reporting from the pentagon, they hope to carry on even longer than that if we wanted in this security environment which is already restricting what they felt they were able to do. i'm sure that we'll have to be a reassessment as to how the gate should be closed for the day and what other operations they are able to do in this now frankly massively changed security environment. there were warnings and fears this could happen. the humanitarian job they were doing was so desperate, so urgent and the soldiers standing there in front of crowds with desperate people brandishing of proof they've been of use over the last 20 years and what some warnl have happened have occurred and it will strike fear in the hearts of anybody trying to get into the airport and remind many afghans too of the dozens of previous attacks like this we've reported on over the last ten, 20 years. random, awful, terrorist violence against civilian masses of people is not daily, but a weekly reality for so many afghans. and here we have this awful scene which appears to have injured u.s. personnel as well and will have an impact on quite how the next few days the closing chapter of america's longest war plays out but it is horrifying to have this incident so warned of come to fruition. >> absolutely. it is a true nightmare scenario. nick, we've been showing as you've been talking a map that is helpful of the lay out of the airport, and the airfield and what is a corridor, an alleyway that becomes a choke point into the airport as you're getting to a prime target for a terror attack. has been warned an warned over and over again in the last couple of days. >> it is awful to start thinking about precisely think being where a target site could have been. but it is this thin corridor of humanity where we've seen people crushed in together and a difficult job for the british soldiers to orchestrate the crowd. there have been crushes there when the u.s. military said claimed seven lives five or six days ago now. it has been awful scenes. and this baron hotel was the filtration point before people got on to the airport proper. many afghans who have through there, it is very hard to get into the airport compound because of the intense security. the vetting. u.s. marines often left to fire in the air at times over my head at one point to get the crowd to come down and move back. one source i spoke to said so much more process would be possible but had the crowd been calmer, but as you're pushing up against the high ten foot tall metal gates as people are all trying to surge forward and make their case. abbey gate, and at risk was the northeast gate. that is where i was at one point briefly too. very tight crowds then there and then elsewhere an area in which afghan security forces have allowed some of their friends and colleagues sneak in. abbey gate, because of the dense series of walls that go along the side of it and the limitations put in place by the sewage canal that run as long part of it, a very terrifying target and one where simply the crowd put people at risk and now it appears we have into that two separate explosions. unclear if this is two bombs or how at tack unfolded. reports of gunfire at the same time as we just saw from a important spokesperson john kirby, this is a referred to as a complex attack and that makes the list of potential suspects smaller. but it is afghanistan and there are many extremists potentially go to go around. the threat stream as u.s. officials have said was from isis-k and we'll have to see how they sort of calculate and grind that in the day as head. but i have to say, so many afghans i have spoken to terrified this could happen. sort of their desperation to get on to the airport. kind of overrid the daily threat with terrorism in their daily lives and have done for a decade, particularly in kabul. but it strikes a chill for me frankly hearing that this is happened. >> i want to re-set. stick with me. and to bring everyone up to speed with the latest update we've received from john kirby. more information, more questions. the pentagon spokesperson saying that we could confirm that the explosion at the abbey gate which we first heard around 9:45 this morning was a result of a complex attack that resulted in a number of u.s. and civilian casualties an said they could confirm one other explosion as we've been discussing with nick paton walsh at or near the baron hotel which is close to the abbey gate. we're waiting, john kirby is updating via twitter. there is supposed to be a pentagon briefing at 10:30. as with everything on the ground has changed and what is going on with the administration right now has changed. let's get over to kylie atwood at the state department. what are you hearing from there? >> reporter: two bits of new news in the tweet from spokesperson john kirby. first of all, this is a complex, in his words, attack. that demonstrates this wasn't just a one-off but many multiple parts to it. and saying there were two at least two explosions. there could have been more. this is clearly an unfolding situation. we're talking to the sources closely monitoring it but it is significant to note that the state department put out an alert to all american citizens saying there was an explosion and saying there were reports of gunfire. so clearly this isn't just the explosions but there are gunfire happening. also, important spokesperson said that one of the explosions happening at the abbey gate. it is significant because that is one of the main gates, the main artery into the airport. where a tremendous number of afghans had been growing in crowds trying to get into that airport, trying to get on these flights. and as we've seen from the early images of what unfolded there, there are afghans who were hurt. we are reporting that there are afghans who died as a result of this explosion. now, abbey gate is one of the gates that the state department said just yesterday that american citizens should not go to. there were some imminent threats in the area and told americans not to go to the airport specifically listing abbey gate at one of those. and as we're watching what is unfolding, questions are going to arise about how does the evacuation continue? we know that there are still americans on the ground in afghanistan as of yesterday, there were between 500 and 1500, presumably some got out overnight. but what does this marine for the americans on ground and we are looking to learn more information about these casualties that john kirby said include both americans and civilians on the ground there. but a tremendously sad, really awful situation for these afghans who have been putting their lives on the line to try and get through these gates, to try and get on these evacuation flights and we know that the u.s. government had been monitoring these terrorist threats in the region specifically against those who were in those crowds outside of the airport. we're seeing this now come to fruition. but this is a quick developing story and a lot more details to figure out, specifically about who was among those casualties and americans and afghans. >> kylie, thank you so much. i want to go to kaitlan at white house. what are you hearing about this. >> reporter: right now the president is in the situation room. getting intelligence about who was involved in the attacks and who was been injured and what are the potential fatalities and that is still information that the white house is getting as the president is huddling with his defense secretary and his secretary of state and the chairman of the join chiefs of staff who were all here at the white house this morning briefing president biden around 9:15 in the situation room and monitoring this attack that the president has been warning was possible since last friday. and saying that this was a fear that they had, that the longer the united states military was in kabul, the higher the risk of an attack would become. and this is already causing some several changes here to this schedule at the white house because there was supposed to be a covid update by that team around 10:30. they have delays that. and in 15 minutes we're to see president biden meeting with the israeli prime minister in the oval office and that is been delayed and there is supposed to be a noon briefing with jen psaki. i'm guessing that is going to be delayed given they're monitoring all of the developments. the question about what changes with the withdrawal is a big one. that is what the white house is still figuring out right now because that is one of the main reasons that president biden did not want to extend the deadline because they were worried about the security situation. they updated the security warning to united states citizens at kabul telling them to get away from the gates at the airport. and these are the crowded gates we've seen on television. president biden is continuing to monitor this. i assume we'll hear from him but a lot is fluid over in the west wing as they are continuing to monitor this and find out what is happened on the ground and of course what the result of this is and of main concern for the president is what and how this effected the u.s. service members who were still there on the ground by the thousands. >> how this changes the evacuation now on the ground at that airport, kaitlan will bring us the updates. i want to get back to do ha and sam you just left kabul airport yesterday and we have learned that there are u.s. and civilian casualties as the pentagon has confirmed and announced. what type of medical capabilities are there at the airport? >> reporter: well, there are the expedition capabilities and the u.s. has a thousand troops an the brits have come in with a thousand. they all travel with their airborne medical facilities and also there is the norwegian military hospital structured on the the base that has four icu beds and had cat scanners and almost all of the modern technology that you would need in a major hospital but on a smaller scale. so in terms of the treatment of any possible casualties, military casualties, they're pretty well set up. most of the casualties clearly from the images we've been seeing on social media are on the ground outside of the camp, dlipgtly targeted in this terrorist attack which has been flagged for sometime, kate. and indeed, we were on the the camp last sunday when the first attack against the camp was conducted. that was a sniper who opened fire, killing a member of the afghan national army, part of the inner perimeter of the coalition. and then there was an ex change of fire in which four more were accidentally wounded by coalition troops. seen in the context of this later attack, that was clearly some sort of probing attack to see what is called ttp's, the standard procedures used in reaction to violence. and this clearly has been the combination. now we have two bombs at least now confirmed by the pentagon. one in a very narrow street up towards the abbey gate. there is a canal and then there is a street and then a long wall of blast walls, which if the blast was on the road, in all probability it might have been, but either way they protect what is on the the other side of it and magnify the blast closer in so the level of casualties likely to be very high and then a second blast near the baron hotel which is the british base of their operations and one of the main routes for refugees and particularly afghans and large numbers of foreigners who get out. so clearly a carefully recognizance target. isis-k members were picksed up by the taliban filming potential targets around kabul. so this is well trailed. but i think the ultimate failure here in terms of security is down to the taliban because they've been screening people coming to the airport. preventing ordinary afghans from escaping and not able to stop the attackers according to the united nations i spoke to in kabul there is concern among the united nations security there that there is more than one attacker and this is a much more complex series of events anz they are deeply concerned there yet be more attacks, kate. >> thank you so much for that. to bring everyone up to speed. what we know at this hour. there have been to explosions at least confirmed by the pentagon outside of the kabul airport in afghanistan. the pentagon confirms there are u.s. and civilian casualties. though no word on the extent of those casualties, how many and how bad it is. there is a alert that came out about an hour ago at this point, the latest alert from the u.s. embassy telling amer