CAIRO, Egypt -- The leader of al Qaeda has confirmed the death of the group's second-in-command in a U.S. drone strike in June.

In a video posted late Monday on militant websites, al Qaeda chief Ayman Al-Zawahri described his late lieutenant Abu Yahya al-Libi as a "lion of jihad and knowledge."

Al-Libi was killed in a U.S. drone strike in northwest Pakistan in June -- the biggest setback to al Qaeda since the death of Osama bin Laden.

Al-Libi was considered a media-savvy and charismatic leader with religious credentials. He rose to prominence in the group after escaping from the U.S. military prison at the Bagram Air Base in Afghanistan in 2005.

His nom de guerre is Arabic for "the Libyan." His real name is Hassan Mohammed Qaid.