Osama bin Laden's long-time lieutenant, Ayman al-Zawahri, is now the leader of al Qaeda, Al Arabiya television said on Thursday, June 16.

The Egyptian-born Zawahri vowed earlier this month to press ahead with al Qaeda's campaign against the United States and its allies, in what appeared to be his first public response to bin Laden's death in a U.S. commando raid in Pakistan in May.

The news channel gave no further details, Reuters reported.

Zawahri, whose whereabouts are unknown, had been seen as bin Laden's most likely successor.