BLITZER: We're getting chilling new information on ISIS plans to attack major population centers. Even before the November slaughter in Paris, western security agencies received intelligence that up to 60 ISIS terrorists had been sent to carry out attacks in five major cities. Our terrorism analyst, Paul Cruickshank, broke the story for us. Paul, tell our viewers what you're learning.</s>PAUL CRUICKSHANK, CNN TERRORISM ANALYST: Wolf, western intelligence prior to the Paris attacks received information, intelligence indicating that up to 60 ISIS operatives had actually come back to Europe to launch attacks on European soil against five cities across Europe, including Paris, where there was eventually an attack, but also London, Berlin, Brussels city or another city in Belgium, Wolf. But this intelligence was fragmentary; it was too vague for them to take specific action.</s>BLITZER: Where are these 60 ISIS fighters now?</s>CRUICKSHANK: They just don't know where they are, because the intelligence was too vague. And so they're very, very worried that they could strike. If, say, 20 were involved in that wider Paris conspiracy, that could mean that 40 could still be at large. That concern was expressed to me by my source. And ISIS itself just yesterday threatened simultaneous terrorist attacks inside Europe in multiple locations at the same time in their French language magazine. And there's real concern now, Wolf, from European officials that ISIS may try to mount a European 9/11 attack as devastating as 9/11 on European soil.</s>BLITZER: Pretty chilling. What a story. Let's -- I know you're working your sources, and you have really good ones. Thanks very much, Paul Cruickshank, for that. Let's take a quick break. When we come back, there are also scary new developments involving North Korea celebrating its rocket launch. An outraged global community views it as a cover for a ballistic missile test, a missile which could one day carry a nuclear warhead. So how will the U.S. respond?
Source: Five Cities Targeted in ISIS Plot