The statement announcing his appointment was posted on a militant website and attributed to al-Qaeda’s General Command.

“Sheikh Dr Ayman al-Zawahiri, may God guide him, assumed responsibility as the group’s amir [leader]”, it said.

It vowed that under Zawahiri, it would pursue jihad or holy war against the US and Israel “until all invading armies leave the land of Islam”…

But our correspondent adds that the delay in announcing Zawahiri as al-Qaeda chief – coming as it does more than six weeks after Bin Laden’s death, despite his being the obvious choice – may point to divisions within the leadership.