Story highlights John Brennan gives a candid assessment of the Middle East

The CIA boss warns that ISIS could use chemical weapons

Washington (CNN) CIA Director John Brennan is questioning whether Syria and Iraq "can be put back together again" given the violence and sectarian tensions in both countries, raising doubts about a central tenet of US policy toward the region.

"I don't know whether or not Syria and Iraq can be put back together again. There's been so much bloodletting, so much destruction," Brennan told the CTC Sentinel , a publication of the Combating Terrorism Center at West Point.

"I question whether we will see, in my lifetime, the creation of a central government in both of those countries that's going to have the ability to govern fairly," he added in the interview which was published Wednesday.

While Brennan has previously called into question Syria's long-term stability, his comments about Iraq, where the government in Baghdad has been a key ally in the fight against ISIS, are likely to rankle officials there.

The US has long called for a unified Iraq, despite sectarian divisions that have led some to recommend a partitioned state.

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