This Oct. 2008 file photo provided by Muhammad ud-Deen, shows radical American-Yemeni Islamic cleric Anwar al-Awlaki in Yemen. (CBS)
WASHINGTON - An American-born cleric killed in Yemen played a "significant operational role" in plotting and inspiring attacks on the United States, U.S. officials said Friday, as they disclosed detailed intelligence to justify the killing of a U.S. citizen.
Anwar al-Awlaki, an American-born radical Islamic preacher who rose to the highest level of al Qaeda's franchise in Yemen, was killed in a CIA-directed strike upon his convoy, carried out with the U.S. Joint Special Operations Command's firepower, according to a counterterrorist official, speaking on condition of anonymity to discuss intelligence.
U.S. officials considered al-Awlaki a most-wanted terror suspect, and added his name last year to the kill or capture list - making him a rare American addition to what is effectively a U.S. government hit-list.
In remarks at the White House Friday morning, President Barack Obama called the death of the jihadist cleric a "major blow" to Al Qaeda in the Arabian Peninsula, and praised the United States' successful alliance with Yemen's security forces.
"This is further proof that al Qaeda and its affiliates will find no safe haven anywhere in the world," Mr. Obama said. "Working with Yemen and our other allies and partners, we will be determined, we will be deliberate, we will be relentless, we will be resolute in our commitment to destroy terrorist networks that aim to kill Americans, and to build a world in which people everywhere can live in greater peace, prosperity and security."
Al-Awlaki was suspected of inspiring or helping plan numerous attacks on the United States, including the Christmas 2009 attempt to blow up a jetliner.
Following the strike, a U.S. official said al-Awlaki specifically directed the man accused of trying to bomb a Detroit-bound plane on Dec. 25, 2009 to detonate an explosive device over U.S. airspace to maximize casualties.
The official also said al-Awlaki had a direct role in supervising and directing a failed attempt to bring down two U.S. cargo aircraft by detonating explosives concealed inside two packages mailed to the U.S. The U.S. also believes Awlaki had sought to use poisons, including cyanide and ricin, to attack Westerners.
Who was Anwar al-Awlaki?The U.S. and counterterrorism officials all spoke on the condition of anonymity in order to discuss intelligence matters.
Multiple terror plots linked to Anwar al-Awlaki
Video: Anwar al-Awlaki urges attacks on Americans
Four individuals were killed in Friday's attack, according to U.S. officials. Yemen's Defense Ministry said another American militant was killed in the same strike alongside al-Awlaki. Samir Khan, a U.S. citizen of Pakistani heritage who produced the English-language al Qaeda Web magazine Inspire that proselytized attacks against the United States. U.S. officials said they believed Khan, from North Carolina, was in the convoy carrying al-Awlaki that was struck by the same U.S. military unit that got Osama bin Laden, but that they were still trying to confirm his death.
His death will deal al Qaeda in the Arabian Peninsula a serious blow, says CBS News terrorism analyst Juan Zarate, particularly his work to draw young Muslims into the jihadi mindset.
"His role as a propagandist actually will be very difficult to fill," says Zarate.
The cleric known for fiery anti-American rhetoric and use of the Internet to spread his message was suspected of inspiring the mass shooting at Fort Hood Army base in Texas in 2009, and taking a more direct role in the attempted Christmas Day bombing of a Detroit-bound jetliner and the planning of other attacks on Americans.
He is the most prominent al Qaeda figure to be killed since bin Laden.
U.S. counterterrorism officials said that counterterrorism cooperation between the U.S. and Yemen has improved in recent weeks, allowing the U.S. to gather better intelligence on al-Awlaki's movements. The ability to better track him was a key factor the successful strike, U.S. officials said. Officials spoke on condition of anonymity to discuss intelligence matters.
Al-Awlaki's death is the latest in a run of high-profile kills for Washington under President Barack Obama. But the killing raises questions that the death of other al Qaeda leaders, including bin Laden, did not.
Al-Awlaki is a U.S. citizen who had not been charged with any crime. Civil liberties groups have questioned the government's authority to kill an American without trial.
Jameel Jaffer, deputy legal director of the American Civil Liberties Union, condemned the drone attack on Awlaki, saying, "The targeted killing program violates both U.S. and international law.
"As we've seen today, this is a program under which American citizens far from any battlefield can be executed by their own government without judicial process, and on the basis of standards and evidence that are kept secret not just from the public but from the courts," Jaffer said. "The government's authority to use lethal force against its own citizens should be limited to circumstances in which the threat to life is concrete, specific and imminent. It is a mistake to invest the President - any President - with the unreviewable power to kill any American whom he deems to present a threat to the country." Al-Awlaki's father filed a lawsuit against the federal government, claiming his son's civil rights were violated by the U.S. call for his killing.
A federal court dismissed Nasser al-Awlaki's suit on Dec. 7, 2010, on the grounds that he had no legal standing to challenge the targeting of his son.
U.S. officials have said they believe al-Awlaki inspired the Fort Hood shooter, Army psychiatrist Maj. Nidal Hasan, who is charged with 13 counts of premeditated murder and 32 counts of attempted premeditated murder in the November 2009 attack at Fort Hood, Texas.
Faisal Shahzad, the Pakistani-American who pleaded guilty to the May 2010 Times Square car bombing attempt, said he was "inspired" by al-Awlaki after making contact over the Internet.
Al-Awlaki also is believed to have had a hand in mail bombs addressed to Chicago-area synagogues, packages intercepted in Dubai and Europe in October 2010.
Al-Awlaki's death "will especially impact the group's ability to recruit, inspire and raise funds as al-Awlaki's influence and ability to connect to a broad demographic of potential supporters was unprecedented," said terrorist analyst Ben Venzke of the private intelligence monitoring firm, the IntelCenter.
But Venzke said the terror group al Qaeda in the Arab Peninsula (AQAP) will remain the most dangerous regional arm "both in its region and for the direct threat it poses to the U.S. following three recent failed attacks," with leader Nasir al-Wahayshi still at large.
Venzke said al-Awlaki was due to release a new article in the next issue of the terror group's magazine, justifying attacking civilians in the West.
"The article, which may already have been completed, was announced by the al Qaeda group on Tuesday as being entitled, 'Targeting Populations of Countries at War with Muslims,'" he said.