The U.S. ushered in a new CIA-led counterterrorism program in Yemen on Friday, sending unmanned aircraft to kill an American-born cleric who occupied a top place on the U.S.'s antiterrorist list.

The death of Anwar al-Awlaki eliminates a leading figure in Yemen's branch of al Qaeda and one of its most charismatic recruiters. A Web-savvy Islamic preacher with sparkling English, Mr. Awlaki was known for his ability to couch extremist views in ways that appealed to Western youth. He had been linked to suspects in the 2009 Fort Hood, Texas, shooting spree and the botched bombing of a Detroit-bound jet that Christmas.

The strike marked another significant blow to the global terrorist group after the killing of Osama bin Laden earlier this year. It also highlights a conundrum about continued joint antiterror operations with the Yemenis: U.S. officials have publicly called for embattled President Ali Abdullah Saleh to accede to the demands of an eight-month-old pro-democracy protest movement and step down from power, but counterterrorism operations are led by close Saleh relatives.

Mr. Awlaki, who had been on the run for months in Yemen's remote tribal regions, was killed at approximately 9:55 a.m. local time outside a village in the northeastern province of Jawf, a Yemeni official said.

At least four people were killed in the operation, Yemeni officials said. These included a second American, Samir Kahn, who was an editor and illustrator for "Inspire," the online magazine of al Qaeda in the Arabian Peninsula.