U.S. officials warn of possible retaliation after al Qaeda cleric is killed

Washington (CNN) -- The killings Friday of alleged terrorists cleric Anwar al-Awlaki and computer expert Samir Khan could spark retaliatory attacks against the United States, according to the FBI and the Department of Homeland Security.
The agencies issued a joint intelligence bulletin late Friday that said supporters might seek to portray al-Awlaki as a martyr in a supposed U.S. war against Islam. It says the deaths "could provide motivation for homeland attacks" by "homegrown violent extremists," the type the two men allegedly tried to recruit or inspire.
The bulletin came less than a day after U.S. and Yemeni government officials announced that al-Awlaki -- an American whose fluency with English and technology made him a top terrorist recruiter -- was killed in a U.S. drone strike in Yemen.
"It was a joint U.S. military-intelligence operation," a U.S. official said, adding that the U.S. military helped target al-Awlaki and that manned American military aircraft were flying overhead ready to offer assistance. The drone was operated by the CIA, officials said.
The strike also killed Khan, an American, and two others who were in the same vehicle as al-Awlaki, said another U.S. official who was briefed by the CIA. Khan specialized in computer programming for al Qaeda and produced the terrorist network's English-language online magazine, Inspire.
The CIA and the Joint Special Operations Command had al-Awlaki under surveillance for at least two weeks, but were awaiting an opportunity to kill him without causing civilian casualties or damage, an administration official said. CIA and Joint Special Operations Command (JSOC) personnel and assets, including drones, were used to track him and to assess how to target him. JSOC, which commands the clandestine U.S. military units, "played a key role in developing the targeting information."
The source said U.S. Marine Corps Harrier jets were flying overhead to provide backup firepower if needed. In addition, troops from the JSOC units were on standby to board V-22 helicopters in the region to rescue potential downed pilots or to conduct operations on the ground if needed. But the only ordnance used came from the drone, the official said.
The official also said the mission, codenamed Operation Troy, was similar to the one in May that killed al Qaeda leader Osama bin Laden in that it was commanded by the CIA, with close coordination with JSOC.
U.S. President Barack Obama called al-Awlaki's death a "major blow" to al Qaeda, reeling still from the killing and capture this year of several top leaders, most notably bin Laden.