possibility of a new attack, the cnn terror analyst paul ku kurbcheck is joining us. isis has claimed involvement in this attack. what are you hearing from your sources? >> reporter: that's right. in fact, two statements from isis, one from its affiliate news agency and one from isis proper, both claiming responsibility for this attack. one saying it was a detachment from the his islamic state that did this and others are saying it was the caliphate that planted multiple devices. now, no evidence that there were multiple devices that were planted. and isis really hasn't offered any evidence to back up its claim that it had a responsibility for this attack. but there is a massive manhunt going on right now in london in the uk for either one suspect or potentially multiple suspects that they might be looking at