ISIS plots discovered befor Paris attacks... Intel says

Intelligence obtained by Western security agencies before theNovember 13 Paris attacks indicated as many as 60 ISIS fighters had been deployed by the group to Europe to carry out attacks on five cities and had already reached European soil, a senior European counterterrorism source told CNN.

The intelligence indicated the target cities included Paris, London, Berlin and a major population center in Belgium, according to the source. It also indicated Abu Mohammed al-Adnani, the head of ISIS' external operations efforts, was the key figure behind the ambitious plan, the source said. There was no indication the plan was to attack the cities simultaneously.

The source cautioned the threat stream was based on intelligence which was fragmentary and difficult to verify, and it was too vague to act on. In addition, there was no specific intelligence prior to the Paris attack on any moving parts of the plot.

"In terms of ambition, it also just pointed towards something we already knew. ISIS had hardly made it a secret it sought to target Europe," said the senior European counterterrorism source.

In the year before the Paris attacks, Adnani had threatened the European countries supporting the anti-ISIS coalition in a series of audio messages, making specific references to France and Belgium. And in January 2015, Belgian police broke up a major ISIS plot in Belgium coordinated byAbdelhamid Abaaoud, who later became the ringleader of the Paris attacks.

The source said Western intelligence agencies believe Adnani is at the heart of ISIS' international attack planning. "As far as we're concerned, he is top of our target list," the source said.

The source said that the lack of specific intelligence on any moving parts of the Paris plot has caused consternation, because it is rare for any plot to fly completely under the radar. In most attacks that have gotten through, Western security agencies had picked up at least some specific chatter on planning, which they later realized related to the attack, the source said.

After the Paris attacks, new attention was focused on the fragmentary intelligence indicating 60 ISIS operatives had been deployed to Europe.

"The worry has been that if, say, 20 were involved in the Paris attacks, there might be 40 or so still out there," the source said.