In a videotape aired on the Al Jazeera news network over the weekend Osama Bin Laden’s deputy welcomed "a number" of the Jamaa Islamiya's leadership "under the al-Qaeda banner."
“They have decided to merge with al-Qaeda to unite the forces of the Muslim nation into one, to face its enemies which are launching the most ferocious campaign ever seen against Islam," he said.
The group is Egypt's main militant Islamist organisation and are believed to be a revived version of a militant faction that waged a campaign of violence in Egypt during the 1990s.
Al-Zawahiri, who is believed to be hiding in the Pakistan-Afghanistan border area with Bin Laden, is himself an Egyptian who was a member of the Muslim Brotherhood before becoming involved in international terrorism.