President Barack Obama ordered a barrage of CIA drone strikes in Yemen in 2013 that killed the al-Qaida operatives behind the most serious plotting against American interests in years, a former CIA leader says in a new memoir that broadly defends the targeted killing of terrorists.

When the U.S. closed 20 diplomatic facilities across the Middle East and Africa in August of 2013, officials said it was in response to intercepted communications about an unspecified plot. They said little about how and why they later deemed the threat abated. But former CIA official Michael Morell says the reason was that that many of the key operatives involved in the plot were killed by U.S. air strikes.

Morell, who retired in 2013 as deputy CIA director after years in leadership posts, offers the most detailed account of the episode to date in a book obtained by The Associated Press ahead of its May 12 publication. Morell says intelligence in July 2013 suggested that al-Qaida in the Arabian Peninsula, or AQAP, was planning a series of attacks against “multiple targets and attacks of significance.”

Although “the intelligence was frustratingly lacking in details” about the intended targets and the timing, Obama closed embassies across the region and unleashed drone strikes on “those AQAP members the United States knew were at the center of the attack plotting,” Morell writes.

The plot, which turned out to be AQAP attacks against American diplomatic buildings in Yemen and Yemeni military installations, was disrupted. “Hundreds of lives were saved,” he wrote.

According to the New America Foundation, which tracks drone strikes, there were nine drone attacks in Yemen between July 27 and Aug. 10, which killed up to 38 militants and possibly two civilians. Morell calls the embassy plot the most serious terrorist threat to face the U.S. since another thwarted al-Qaida plan in 2006 to bring down multiple airliners over the Atlantic Ocean.

Morell’s book, “The Great War of Our Time,” recounts his 30 years as a CIA analyst, with a particular focus on his work in counterterrorism. The book includes significant criticisms of the CIA, accusing the agency of failing to anticipate that the political upheaval across the Arab world could lead to a resurgence in extremism by al-Qaida and related groups.

Morell also explores the CIA’s missteps in assessing that Saddam Hussein’s Iraq had weapons of mass destruction, taking the opportunity to “publicly apologize” to former Secretary of State Colin Powell, who relied on wrong information provided by intelligence agencies when he made the case for Iraq WMD before the United Nations.

And Morell pointedly criticizes the National Security Agency, saying it was conducting highly sensitive surveillance of allied leaders without fully considering the appropriateness of its operations.

The NSA, he said, “had largely been collecting information because it could, not necessarily in all cases because it should.”

But Morell, who was traveling with President George W. Bush on 9/11 and was involved in the intelligence behind the raid that killed Osama bin Laden in 2011, mounts a staunch defense of two controversial CIA programs: brutal interrogations of al Qaida prisoners and targeted killing with drones.

While Morell says he is personally troubled by the harshest technique the CIA used on detainees, water boarding, he makes a case that agency leaders had no choice but to use what many consider torture in the years after the 9/11 attacks. He said such techniques saved American lives.

It is difficult for CIA officers to legally talk about the agency’s drone strikes, because they are technically covert and deniable. Morell therefore omits many details as he vigorously defends what he calls “the single most effective tool in the last five years” for counterterrorism.

Drones strikes result in minimal civilian casualties, he says, and claims to the contrary are “highly exaggerated,” flowing from propaganda.

But Morell does not address whether the CIA has ever aimed its precision weapons at the wrong target based on faulty intelligence. Nor does he speak to the issue of signature strikes in Pakistan — attacks ordered against people who fit the terrorist profile, but whose identities are not known by the agency.

One such strike killed dozens of innocent miners in Pakistan in 2011, Pakistani officials insist. Another resulted in the deaths of two Western hostages last month.

(AP)