Obama: Anwar Al-Awlaki death is major blow for al-Qaeda
US President Barack Obama has said the death of senior US-born al-Qaeda leader Anwar al-Awlaki in Yemen is a "major blow" to the organisation.
Yemen said Awlaki was killed in Jawf province, along with several of his associates - US officials said US drones had carried out the attack.
Awlaki, who was of Yemeni descent, was a key figure in al-Qaeda in the Arabian Peninsula (AQAP).
He is believed to have been behind a number of attempts to attack the US.
Mr Obama said that as a leading AQAP figure, Awlaki had taken the lead in "planning and directing efforts to murder innocent Americans" and was also "directly responsible for the death of many Yemeni citizens".
He said Awlaki had directed attempts to blow up US planes and had "repeatedly called on individuals in the United States and around the globe to kill innocent men, women and children to advance a murderous agenda".
His death, said Mr Obama, "marks another significant milestone in the broader effort to defeat al-Qaeda and its affiliates".
The president also paid tribute to the work of both the US intelligence agencies and Yemeni security officials who had co-operated on the killing.
"This is further proof that al-Qaeda and its affiliates will find no safe haven anywhere in the world," he said, but warned that AQAP "remains a dangerous though weakened terrorist organisation".
In a brief statement on Friday, Yemen's defence ministry statement said Awlaki had been killed in Khashef in Jawf about 140km (90 miles) east of the capital, Sanaa, "along with some of his companions".
US and Yemeni officials later named one of those as Samir Khan, also a US citizen but of Pakistani origin, who produced an online magazine which promoted al-Qaeda's ideology and gave instructions for making bombs.
Unnamed US officials said Awlaki's convoy had been hit by a US drone strike, but Mr Obama has not commented on this.
BBC security correspondent Gordon Corera says the killing is significant because Awlaki's use of modern media enabled him to reach out to and inspire people susceptible to radicalisation.
He is accused of
- recruiting and preparing Umar Farouk Abdulmutallab, the Nigerian man who tried but failed to bomb a Detroit-bound airliner on Christmas Day 2009
- overseeing a failed plot to blow up two US-bound cargo planes in 2010 with explosives hidden in printer cartridges
- encouraging US Maj Nidal Malik Hasan to carry out the 2009 US army base killings in Fort Hood, Texas which killed 13 people
- inspiring the man who carried out a failed bombing in New York's Times Square in 2010
- inspired a British women to stab her MP Stephen Timms over his support for the war in Iraq
- plotting to use poisons including cyanide and ricin in attacks
- repeatedly called for the killing of Americans, saying in a 2010 video online that they were from the "party of devils"
Mr Obama is said to have personally ordered Awlaki's killing in 2010, but the al-Qaeda leader has survived several attempts on his life.
Late last year, he survived an air strike in Shabwa province in which at least 30 militants were killed. He was also the target of a US drone attack on 5 May which killed two al-Qaeda operatives in southern Yemen.
However, some in the US have criticised the administration's targeted killing of a US citizen abroad, arguing he should have been arrested and put on trial.
Republican congressman Ron Paul - an opponent of the wars in Iraq and Afghanistan - said the killing amounted to an assassination.
"He is an American citizen. He was never tried or charged with any crime. Nobody knows if he killed anyone," he told ABC News.
However, the BBC's Mark Mardell in Washington says that despite the fact Awlaki appears to have been targeted for his words rather than actions, very few Americans are likely to be concerned about any infringement of his rights.
In a news briefing, White House spokesman Jay Carney would not give further details on the operation but said his role "has been well established" and that AQAP presented a "definite threat" to the US.
The killing comes amid concerns in Washington about the impact of Yemen's political crisis on its ability to tackle al-Qaeda militants.
President Ali Abdullah Saleh is facing a widespread protest movement, along with an armed insurrection by renegade army units and tribal fighters.
Mr Saleh, who was injured three months ago when his residence was shelled, returned last week after treatment in Saudi Arabia.
In an interview published on Thursday, he said he would not stand down, as promised in a deal brokered by Gulf States, if his opponents are allowed to stand in elections to succeed him.