A drone strike in the eastern Yemeni province of Shabwa last month killed the top religious cleric for Al-Qaeda in the Arabian Peninsula (AQAP), a source close to the group said on Tuesday.

“A drone strike had targeted Sheikh Adel al-Abab’s vehicle but he escaped and fled to a mountainous region where a raid by another drone killed him immediately,” the source told AFP on condition of anonymity.

Abab had graduated from the Dawa Islamic studies center, in Sana’a and had served as the top religious cleric for AQAP.

American drone strikes against Al-Qaeda terrorists are frequent in Yemen, home of the network believed by the United States to be the deadliest and most active of the jihadi terrorists.

AQAP is led by Nasser al-Wuhayshi, who in July 2011 reaffirmed the group’s allegiance to Ayman al-Zawahiri, head of the worldwide Al-Qaeda network since the killing in May of its founder, Osama bin Laden.

U.S. drones strikes in Yemen nearly tripled in 2012 compared with 2011, from 18 to 53, according to the New America Foundation, a Washington-based think tank.

In October 2000, Al-Qaeda terrorists attacked U.S. Navy destroyer the USS Cole in Yemen’s port of Aden, killing 17 sailors and wounding 40 more.