Trump and clinton now running neck and neck. Theres some discussion tat your supporters might in a general election if you dont make the nomination go over to donald trump. Donald trump is a disaster, and i will do everything i can to see that he is defeated. President obama is beginning a historic visit to vietnam. The United States is fully lifting the ban on the sale of military equipment to vietnam that has been in place for some 50 years. Looking to take back one of the key cities held by isis. Operations to retake fallujah efforts have expanded to recover the black boxes from flight 804. The Billboard Music awards filled with memorable moment. Purple rain unlike the oscars, we actually have black nominees this evening. You hear what im saying . The weekend. I love you, thank you. Tornadoes touched down in texas bringing heavy rains and damaging winds. Dead, lets go, please at the white house, someone spotted mystery objects flying over the ground prompting a lockdown. It turns out it was a few stray party balloons. All that chewbacca masks are flying off the shelves thanks to this texas woman. [ laughter ] green going for the layup, kicking steven adams lets see he gets the New Zealander right in the kiwi. And all that matters celine dion gave a powerful performance. This ones for you. [ speaking french ] [ applause ] on cbs this morning. You should be proud, you know. You ran a damn good campaign. Im running a good campaign. But dont worry, i promise im going to have a special role for you in my administration. How would you like to be wait for it the senator from vermont . [ laughter ] welcome to cbs this morning. In an historic move, president obama has lifted an arms embargo on vietnam. The president announced the move overnight at a meeting with vietnams president in hanoi. The embargo has been in effect since the vietnam war. The two leaders pout a show of solidarity in the face of growing tension with china. Margaret brennan is traveling with the president in happen ohio. Good morning. Reporter good morning. President obama is here to build Stronger Economic and security ties with vietnam. That decision to lift the arms embargo is aimed at sending a message to china that the u. S. Will not let it militarily dominate asia. With a warm welcome from vietnams communist government, president obama tried to put to rest the ghost of the brutal war with the u. S. That killed tens of thousands of people from both countries. Just a generation ago we were adversaries, and now we are friends. Should give us hope. Reporter the vietnamese are eager to build ties with our cold warera foe in large part because of the threat posed by militarily aggressive china which is seizing territory in the east and south china seas. In an effort to stop that land grab, president obama made the decision to sell vietnam americanmade weapons, removing a ban thats been in place for over four decades. A controversial decision since vietnam is controlled by an authoritarian regime. The change will ensure vietnam has access to equipment it needs to defend itself and removes a lingering vestige of the cold war. Reporter in exchange, vietnam will give u. S. Ships more access to its ports. Mr. Obamas next stop on the trip will be to another former enemy japan. Hell make a historic trip to the city of hiroshima, the first sitting president to do so. That city was decimated in 1945 when the u. S. Dropped the very first atomic bomb during world war ii. More than 100,000 died. President obama told Japanese Television that he will not apologize. Because i think that its important to recognize that in midst of war, leaders make all kinds of decisions. Reporter now the white house says the president will not revisit the decision to drop the bomb, but he will say that it gives america the unique responsibility of making sure that a Nuclear Weapon is never used again. All right. Margaret brennan, thank you very much. New polls show that the race for the white house has dramatically tightened. In march and april, Hillary Clinton had a big lead in a headtohead matchup with donald trump. That advantage has evaporated. She leads by just three points in one poll and is losing to donald trump in another. Nearly half of the voters say they want to consider a thirdparty option in november. Nancy cordes has a closer look at the changing race. Good morning. Reporter good morning. Clinton says she doesnt Pay Attention to the polls, but clearly her campaign is feeling some pressure to begin focusing on her general election candidate as she and her husband unveiled some new attacks on trump. What make America Great again means is, hey, ill make it the way it used to be. You will be better off, and if youre not, at least youll have somebody else to look down on. That is a dumb idea. It will not work. Reporter campaigning in california, bill clinton mocked Donald Trumps slogan make America Great again previewing one of his wifes key strategies. Were not going to let at least my campaign is not going to let donald trump try to normalize himself. Reporter new battleground polling from florida and ohio shows voters think clinton is far more prepared than trump to be commander in chief. But they said trump is far more likely to tell it like it is. They were also more likely to say he is too extreme. [ applause ] clinton may be ready to focus on trump, but sanders reminded polls show hed be the stronger challenger. If we get the nomination, i guarantee donald trump will not be president. Reporter clinton argued sanders only polls better because he hasnt been subjected to republican attacks the way she has. I dont think hes had a single negative ad ever run against him. Reporter in california and in interviews, sanders continues to lump clinton in with trump. I dont want to see the American People voting for the lesser of two evils. This campaign is reporter sanders, who only recently became a democrat, has repeatedly clashed with the partys chair, congresswoman Debbie Wasserman schulz. This weekend he began raising money for her florida primary opponent. I like debbie. Do i think she is the kind of chair that the Democratic Party needs . No, i dont. Reporter hes long argued that she favors clinton over him, while she criticized him last week for not doing enough to calm unruly supporters in nevada. In the fundraising email that his campaign put out last night, they pointedly said that electing her progressive opponent will send an unmistakable message to the Democratic Party. Gay rights is the newest issue dividing gun rights is the newest issue dividing donald trump and Hillary Clinton. Clinton spoke to mothers over the weekend who lost children to gun violence. Chip reid looks at how both candidates have changed positions on the issue. Good morning. Reporter good morning. Both trump and clinton think they can win on the issue of guns, and over the weekend, the Second Amendment became one of the first topics to get the candidates to engage each other in what could be a preview of a general Election Campaign fight. Ladies and gentlemen, the next president of the United States, donald trump. Reporter when donald trump accepted the endorsement of the National Rifle association, he wasted no time firing shots at Hillary Clinton. Hillary clinton wants to abolish the Second Amendment. Just remember that. Reporter clinton certainly hasnt proposed getting rid of the right to bear arms, but her campaign is seizing on trumps past position on guns in schools. I will get rid of gunfree zones in schools my first day it gets signed, okay . That idea isnt just way out there, its dangerous. Reporter at an event in battleground florida for mothers who have lost children to gun violence, clinton fired back. Parents, teachers, and schools should have the right to keep guns out of classrooms. Just like donald trump does at many of his hotels, by the way. Reporter trump tweeted that clinton was wrong regarding his position on guns in schools, but he struggled to clarify sunday. I dont want to have guns in classrooms, although in some cases teachers should have guns in classrooms, frankly. Reporter the issue is tricky for both campaigns. Many democrats cite bill clintons assault weapons ban as one of the reasons they lost big in the 1994 elections. And in 2008, Hillary Clinton struck a much different progun tone in her president ial run. Thencandidate barack obama called her out. She values the Second Amendment. Shes talking like shes annie oakley. Reporter trump hasnt always sided with the nra on gun policies. In 2000, in his book the america we deserve, trump wrote, i support the ban on assault weapons and a slightly longer waiting fo ing period to purchase a gun. Two positions he now opposes. Cbs checked with hotels and resorts bearing the trump name. Some claimed to be gunfree zones. Others allow guests to carry a firearm with the proper permits. Norah . Thank you very much. Isis claims responsibility for several deadly bomb attacks in syria this morning. A Human Rights Monitoring Group says more than 120 people were killed. The blast apparently targeted supporters of syrian president Bashar Al Assad. The explosions along the countrys mediterranean coast included a suicide bombing at a hospital. Elizabeth palmer is tracking developments from london. Good morning. Reporter good morning. The bombs went off between 9 00 and 10 00 local time, just when the city was geearing up for th day. Mayhem is exactly what was intended. Casualties, charred wreckage and above all, terror. A reminder that isis is able to strike anyone anywhere with suicide bombers who can sneak themselves and their bombs even to the most heavily protected areas. The cities they struck this morning are in the heartland of the syrian regime. Its where president Bashar Al Assad comes from. The very center of his support is there. And until now, an area thats been safe enough that on our last visit we found syrians on the beach, convinced that they were secure enough to forget at least for a while that their country is at war. I anymore. The isis bombings also send a very provocative message to president putin. The russians have two military bases in this area which theyve been using to support the syrian army in its battle against the various rebel groups. Gayle . Thank you, elizabeth. Iraqs military is attempting to take the city of fallujah back from isis this morning. The terror group has controlled the city about 40 miles west of baghdad for more than two years now. Iraqs Prime Minister announced the new offensive last night. His government has told fallujah residents to get out. Our david martin reports there are up to 1,000 isis fighters in fallujah. Thats compared to more than 20,000 iraqi forces. U. S. Advisers will not go forward with the troops. President obama confirms this morning that an american drone strike killed a taliban leader. A French News Agency says this video shows mullah maktar mansours burned out car. The drone strike was in a remote part of pakistan near the afghan border. Pakistans Prime Minister condemned the attack. The president says mansour was an obstacle to peace efforts with the taliban. An underwater search will try to locate the black boxes from egyptair flight 804. The u. S. Navy found more than 100 pieces of debris on the surface over the weekend. The flight from paris to cairo crashed early thursday killing all 66 on board. The International Search effort is focused off the egyptian coast. Holly williams in cairo has the latest on the investigation. Good morning. Reporter good morning. The Egyptian Government has sent a submarine to the search area to try to retrieve the planes flight recorders or socalled black boxes which could finally explain what went wrong. The first audio recording to be released from the planes flight deck is a standard checkin between the pilot and air Traffic Control over zurich in switzerland. 0725, thank you very much, good day. Good night. Reporter around 2. 5 hours later, the plane began to move erratically and then plummeted, disappearing off radar screens and plunging into the water. The search area is around 180 miles north of the evip egypt coastline where an American Team spotted wreckage, and the Egyptian Military retrieved debris from the crash. Data published by an Aviation Industry website appears to show automated transmissions from the plane in the minutes before it crashed, indicating there was smoke on board, though experts say the smoke alarms could also have been triggered by a sudden loss of pressure. Will alstair rosenshein is a former pilot with british airways. It means Something Big happened with the aircraft. Multiple failures means theyre in serious trouble. Thats not a normal situation. Could be caused by an explosion. Could be caused by fire. Reporter no possible cause has been ruled out at this stage, including terrorism. Though u. S. Investigators have told us that so far theres been no credible claim of responsibility. Gayle . Holly williams in egypt reporting. Thank you. A man suspected of killing a Massachusetts Police officer is dead this morning after a shootout. Police say that Jorge Zambrano opened fire last night. His officers searched an apartment. A state trooper was wounded. Zambrano was supported in the shooting of officer ronald tarantino. He was killed early sunday during a traffic stop an hour west of boston. The threat of thunderstorms and tornadoes will continue across the midwest this week. Daddy, lets go, please at least one tornado touched down in central texas. Several more were reported in the panhandle. No injuries or damage were reported. More heavy rain hit north center nebraska yesterday. Cars were swamped in one town as lightning flashed overhead. New details of princes death are emerging. A report says that the legendary pop star was likely dead for hours when his body was found in the elevator at his minnesota estate. The story comes as madonna honored prince at last nights Billboard Music awards in las vegas. Jamie yuccas has a look at the starfilled event. A great show. Good morning. Reporter it was quite a night. Good morning to you. The night was filled with emotional and electric performances, renditions of old hits, political statements, and a moving tribute for a late pop icon. Purple rain purple rain reporter it was a tribute fit for a prince. The material girl, madonna, stevie wonder, and a sea of loving fans belted out one of the late pop superstars greatest hits. Purple rain purple rain reporter in front of a packed las vegas house. Celine dion showed she can still command a room. Performing with a heavy heart after the loss of her husband earlier this year. She fought back tears as her son presented her with the billboard icon award. [ cheers ] reporter it was a night full of emotion. Keshas powerful cover of bob dyl dylans it aint me babe was celebrated with a standing ovation. A legal dispute with her record producer almost prevented the singer from taking the stage. Reporter Britney Spears partied like it was 1999. Reporter in a rare award show performance, turning back the clock to revive her greatest hit unafraid ill be 60 years old reporter the night was also a celebration of whats hot in popular music. Reporter there was no shortage of fireworks. Cool for the summer reporter including demi lovatos shirt. Highlighting an inclusive bathroom symbol and her support for the transgender community. Reporter by the way, there was some hardware handed out, too. The weekend collected the most awards of the night with eight. Wow. It was worth staying up late for. That was a touching scene with celine and her son because she didnt know her son was coming out. She started crying and said, i try not to cry in front of my children, as most mothers do. She didnt want to cry in that moment. She kept saying, im sorry i was crying. Interesting outfits. Britney spears little number . Youd look good in that, norah. Maybe for halloween. She looked good in it, though. Got to hand it to her. Thank you very much. Now this story which is coming up one of americas most notorious domestic terrorists insists hes not crazy. Ahead, the new letter from the unabomber. A busy climbing season on mt. Everest takes a sudden turn. Ahead, the deadly consequences of extreme conditions on the worlds tallest mountain. 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