Al Qaeda's new leader Ayman al-Zawahri
Al Qaeda's new leader Ayman al-Zawahri is shown in this undated file photo. Reuters

Al-Qaeda has declared Ayman al- Zawahiri as its new leader after the killing of Osama bin Laden in a U.S. raid in Pakistan Last month, the dreaded terrorist group said in a statement on Thursday.

An Egyptian surgeon, Zawahiri has been the top lieutenant of Laden for years. He has also been the public face of al-Qaeda for a long period of time, appearing in video and audio messages to threaten more attacks against Western targets, a Bloomberg report said.

We ask God for this to be a new era for al-Qaeda under the leadership of Ayman Al-Zawahiri, an era that will purify Muslim land of every tyrant and infidel, al-Qaeda said in a statement posted on a website frequently used by the terrorist group.

In 1999, Zawahiri was indicted in absentia for the August 1998 bombings of U.S. embassies in Tanzania and Kenya, which killed 224 people. He was also accused of being the mastermind of the bombing of the USS Cole in Yemen in October 2000 that killed 17 sailors.