A campaign of more than 40 U.S. air strikes against Al-Qaeda in Yemen killed a former detainee at Guantanamo Bay who was released in 2009 despite being considered a "high threat," the Pentagon said on March 6.

Mohammed Tahar, a Yemeni also known as Yasir al-Silmi, was a prisoner in Cuba for seven years and was killed on March 2, it said.

Also killed in the same strike was Usayd al-Adani, an explosives expert and leader of Al-Qaeda in the Arabian Peninsula, the Pentagon added.

A March 2008 memo from the Guantanamo commander assigned a "high risk" to Tahar and warned that he would "engage in extremist activities upon release" because he "continues to support jihad."

Tahar was released in 2009, when newly elected President Barack Obama was starting to carry out his campaign pledge to close Guantanamo.

In 2010, the U.S. stopped releasing Yemeni detainees because most countries were unwilling to take them, and it was difficult to ensure they would not return to the battlefield if allowed to return home.

About 55 detainees who remain at Guantanamo today are Yemeni, including some who have been cleared for release. Four were released in January, and were sent to Saudi Arabia.

Based on reporting by AP, AFP, Reuters, and dpa