US President Barack Obama said on Friday the killing in Yemen of Anwar al-Awlaki, a US-born cleric, was "another significant milestone" in efforts to defeat al-Qaida and its allies."This is further proof that al-Qaida and its affiliates will have no safe haven anywhere in the world," Obama said, adding that Awlaki's death was a result of the government of Yemen joining international efforts against the militants.RELATED:Analysis: The US goes after epicenter of al-Qaida’s online networkAl-Awlaki advocates killing in new videoAwlaki, identified by US intelligence as "chief of external operations" for al-Qaida in the Arabian Peninsula, was killed in a CIA drone attack in a remote Yemeni town, US officials said."The terrorist Anwar al-Awlaki has been killed along with some of his companions," Yemen's Defense Ministry said in a statement sent by text message to journalists earlier Friday, but gave no details.A Yemeni security official said Awlaki, who is of Yemeni descent, was hit in a Friday morning air raid in the northern al-Jawf province that borders oil giant Saudi Arabia. He said four others killed with him were suspected al-Qaida members. Awlaki had been implicated in a botched attempt by AQAP to bomb a US-bound plane in 2009 and had contacts with a US Army psychiatrist who killed 13 people at a US military base the same year.US authorities have branded him a "global terrorist" and last year authorized his capture or killing, but Sanaa had previously appeared reluctant to act against him.Eloquent in English and Arabic, Awlaki encouraged attacks on the United States and was seen as a man who could draw in more al-Qaida recruits from Western countries.Yemen has been mired in turmoil after eight months of mass protests demanding an end to Saleh's 33-year rule. International powers have feared the unrest has emboldened AQAP. Militants with suspected links to the group have seized towns in a southern coastal province near a strategic shipping lane.One analyst said Awlaki's killing would be more of a boon to Yemeni President Ali Abdullah Saleh than a loss for AQAP, seen as one of al-Qaida's most aggressive and dynamic wings."For AQAP, these franchises are usually resilient. There are other capable leaders in AQAP who can fill his shoes," said Theodore Karasik, security analyst for the Dubai based INEGMA group. "It's a short step backwards which will likely result in more assertion in the future, for the revenge of his martydom."However, Awlaki, if his death is confirmed, may not be so easy for AQAP to replace. He may not be a very senior Islamic cleric, nor is he AQAP's leader - that is Nasser al-Wuhayshi - but he ranks as its most gifted English-language propagandist. Britain's intelligence chief John Sawers singled him out as a major threat with a global appeal in a speech last October. "From his remote base in Yemen, al-Qaida leader and US national Anwar al-Awlaki broadcasts propaganda and terrorist instruction in fluent English, over the Internet," he said.