CIA Director: Battlefield Advances Have Not Degraded ISIS' Terrorism Potential

The director of the Central Intelligence Agency told the Senate Intelligence Committee on Thursday that the U.S. and its allies are making progress on the battlefield against the Islamic State.

But then John Brennan dropped a major caveat.

"Unfortunately, despite all our progress against ISIL on the battlefield and in the financial realm, our efforts have not reduced the group's terrorism capability and global reach," Brennan said. "The resources needed for terrorism are very modest, and the group would have to suffer even heavier losses of territory, manpower and money for its terrorist capacity to decline significantly."

Brennan said ISIS has lost lots of ground in Iraq and Syria and that its finances have been squeezed. ISIL, Brennan said, using another acronym for the group, is on the defensive.

"To compensate for territorial losses, ISIL will probably rely more on guerrilla tactics, including high-profile attacks outside territory it holds," Brennan said. "A steady stream of attacks in Baghdad and Damascus demonstrates the group's ability to penetrate deep inside enemy strongholds."