Key al Qaeda figure killed as ranks dwindle

A senior al Qaeda leader who has been described as a key operational figure for al Qaeda in Pakistan has been killed, a U.S. official confirmed to CBS News Thursday.

Abu Hafs al-Shahri was a core leader in the militant group, most recently as an operations planner working with the Pakistani Taliban in coordinating attacks in the in the border regions of Afghanistan and Pakistan, reports CBS News national security correspondent Bob Orr.

His death should pose an additional challenge for Ayman al-Zawahiri, al Qaeda's new leader after the death of Osama bin Laden. He is the most recent of several top al Qaeda figures killed and was thought to be among the top five leaders in the militant group. He was considered a contender to replace some duties of al Qaeda's second in command, Atiyah Abd al-Rahman, the official said.

Al-Rahman was killed by a CIA drone strike in late August, which is apparently how al-Shahri was also killed, though U.S. officials refused to confirm the method since the drone program is classified.

The killing was first reported by NBC News.