CIA failed to predict al-Qaeda's rebound, former deputy director Michael Morell claims

US intelligence agencies badly misjudged al-Qaeda's ability to take advantage of political turmoil in the Middle East and regain strength across the region after Osama bin Laden was killed, according to a new book by the CIA's former deputy director.

Senior US intelligence officials have previously acknowledged failures to anticipate the Arab Spring movement, which toppled governments in the Middle East and North Africa. But the former official, Michael Morell, wrote that the CIA compounded those errors with optimistic assessments that the upheaval would eventually prove devastating to al-Qaeda.

"We thought and told policy-makers that this outburst of popular revolt would damage al-Qaeda by undermining the group's narrative," Morell wrote in the book, a copy of which was obtained ahead of its release later this month.

Instead, "the Arab Spring was a boon to Islamic extremists across both the Middle East and North Africa," he said.

"From a counterterrorism perspective, the Arab Spring had turned to winter."

The acknowledgment represents one of the most bleak assessments of the CIA's performance during that period by an official who was in the agency's leadership at the time.