Osama bin Laden's right-hand man Ayman al-Zawahiri claimed in a video message that a radical Algerian Islamist group had joined Al-Qaeda and warned it would be a "thorn in the throat" of the West.
"Osama bin Laden has told me to announce to Muslims that the GSPC (the Salafist Group for Preaching and Combat) has joined Al-Qaeda," Zawahiri said, according to extracts of the video issued this week to coincide with the fifth anniversary of the September 11 attacks on the United States.
"We pray to God that they will be a thorn in the side of the American and French crusaders and their allies," he said.
The GSPC, created in 1998 by dissidents from the Armed Islamic Group (GIA), rejects Algerian President Abdelaziz Bouteflika's policy of reconciliation and is regarded as the only radical Islamist movement left in the country capable of causing serious trouble.
The GIA was largely dismantled by the security services in January.
"This should be a source of chagrin, frustration and sadness for the apostates (of the regime in Algeria), the treacherous sons of (former colonial power) France," Zawahiri said of the GSPC's links to Al-Qaeda.
"We pray to God that our brothers from the GSPC succeed in causing harm to the top members of the crusader coalition, and particularly their leader, the vicious America."
In the video, first released on Sunday, Zawahiri issued new threats against the West, warning that the Gulf and Israel would be the next targets of Al-Qaeda.