about 2,500 strong when the tension escalated. it happened not far from where president obama and more than 50 world leaders were juggling issues facing afghanistan and nato. the city s top police officer blames a small group of trouble-makers. there was a group of what we commonly refer to as the black bloc folks who kind of rallied together, they put their masks on, and we had intelligence from the crowd that as soon the ceremony from the soldiers were over that they were going to charge the stage and try to break through and assault our cops. that s exactly what happened. they rallied. y that charged the cops, and they assaulted the officers. we responded. so far today we re up to 45 arrests today. and tonight has a live report from down there where the crowd was earlier. paul, you were right in the middle of all that have when it got violent. you were down there today. who did what to trying they are mess? reporter: don, when you re looking at that from the inside o