WASHINGTON (AFP) - Al-Qaeda chief Ayman al-Zawahiri declared on Wednesday in a video message that the global Islamist extremist movement has launched a new branch to lead its struggle in the Indian sub-continent.

In the video, found in online jihadist forums by the SITE terrorism monitoring group, Zawahiri said the new force would "crush the artificial borders" dividing Muslim populations in the region.

Al-Qaeda is active in Afghanistan and Pakistan, where its surviving leadership are thought to be hiding out, but Zawahiri said "Qaedat al-Jihad" would take the fight to India, Myanmar and Bangladesh.

"This entity was not established today but is the fruit of a blessed effort of more than two years to gather the mujahedeen in the Indian sub-continent into a single entity," he said.

Founded by Osama bin Laden, who was killed in Pakistan by US commandos in May 2011, Al-Qaeda has long claimed leadership of the jihadists fighting to restore a single caliphate in Muslim lands. But since the death of its figurehead, it has been somewhat eclipsed, first by its own offshoots in Africa and the Arabian Peninsula, and now by the so-called "Islamic State" fighting in Iraq and Syria, also known as ISIS.

While still regarded as a threat to the West, the group has never managed to repeat the spectacular success of the September 11, 2001 attacks by hijacked airliners on New York and Washington. But, in launching "Qaedat al-Jihad in the Indian sub-continent," in a video partly in his native Arabic and partly in the Urdu of his presumed Pakistani base, Zawahiri attempted to regain some of the limelight.

"It is an entity that was formed to promulgate the call of the reviving imam, Sheikh Osama bin Laden. May Allah have mercy upon him," Zawahiri said. He called on the "umma," or Muslim nation, to unite around "tawhid," or monotheism, "to wage jihad against its enemies, to liberate its land, to restore its sovereignty and to revive its caliphate."

He said the group would recognize the overarching leadership of the Afghan Taleban leader Mullah Muhammad Omar, be led by Pakistani militant Asim Umar, and employ a spokesman.