(AP) An American was believed to be among the six militants killed in a CIA missile strike this weekend, a security source said Thursday.

The six men, including Qaed Salim Sinan al-Harethi, al Qaeda's top man in Yemen, were killed Sunday when a Hellfire missile fired from a pilotless CIA spy plane destroyed the car they were riding in.

The source, speaking on condition of anonymity, said the other five were known by their aliases — Saleh Abu Hamam, Al-Qia'gaa, Abu Jirah, Mounir and Jalal, also known as Ahmed Hijazi. Jalal is believed to be a U.S. citizen, according to the source. He provided no other details and did not say how authorities came to establish that Jalal was American.

Authorities were trying to establish the men's real identities, the source told The Associated Press.

He said al-Harethi, who was in his mid-40s, first met al Qaeda leader Osama bin Laden in the 1980s during the war against Soviet occupation in Afghanistan. The two men stayed in contact after the war ended and met again in Sudan, where bin Laden went to in the 1990s, the source said.

Al-Harethi was believed to have coordinated the October 2000 attack on the USS Cole in Aden, which killed 17 U.S. sailors.

A Yemeni newspaper, September 26, reported that al-Harethi plotted last month's attack on the French tanker Limburg off Yemen, which left a Bulgarian crew member dead and 90,000 barrels of oil discharged in the Gulf of Aden. The newspaper did not cite sources.

The newspaper, whose editor-in-chief is President Ali Abdullah Saleh's press secretary, also reported that al-Harethi was responsible for several terror attacks in Yemen and was planning more attacks on Western targets in Yemen.

On Wednesday, the U.S. Embassy in the capital San`a closed for security reasons and protection of the building was increased. There were fears that the CIA involvement in the attack could create a backlash in a country where Islamic militants have operated freely in the past and most oppose U.S. policies toward Iraq and the perceived American bias toward Israel in its conflict with the Palestinians.

Yemen's cooperation with U.S. authorities in the war against terror is a sensitive issue in this Arab country, where al Qaeda is active and is the ancestral homeland of bin Laden.