Al-Qaeda has appointed Ayman al-Zawahiri as leader following the death of Osama Bin Laden, the organisation's general command says in a statement.
Bin Laden was killed by US forces in Pakistan in early May.
In the statement, al-Qaeda "announces that Sheikh Dr Ayman al-Zawahiri, may God guide him, assumed responsibility as the group's amir [leader]".
It warned it would continue to fight a jihad or holy war against the US and Israel under his direction.
Zawahiri is believed by some experts to have been the "operational brains" behind the 9/11 attacks on the US.
He was Bin Laden's deputy for years and warned just over a week ago that Bin Laden would continue to "terrify" the US from beyond the grave.
For years security analysts have suggested Zawahiri is most likely to be hiding in the Afghan-Pakistan border region.
http://www.bbc.co.uk/news/world-middle-east-13788594
Note: 16 June 2011 Last updated at 07:12 GMT