Al-Qaeda leader Ayman al-Zawahiri has announced the formation of an Indian branch of his global armed group that he said would spread Islamic rule and "raise the flag of jihad" across the subcontinent.

In a video spotted in online "jihadist" forums on Wednesday 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 the group 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 self-declared 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.

While still regarded as a threat to the West, the group has never managed carry out another attack on the scale 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," Zawahiri may be attempting to recapture some of the limelight for his group and to exploit existing unrest in Kashmir and Myanmar.

"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.

'Waging jihad'

Zawahiri 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 recognise the overarching leadership of the Afghan Taliban leader Mullah Muhammad Omar and be led day-to-day by senior Pakistani fighter Asim Umar.

The 55-minute video begins with stock footage of the late bin Laden giving a sermon, before cutting to a satellite map of southwest Asia, the Middle East, the Indian sub-continent and the Horn of Africa.

Then it cuts to a white-bearded Zawahiri, in a white turban and glasses, against the backdrop of a brown floral curtain and desk with hardback books and a tin holding ballpoint pens and prayer beads.

Umar also speaks in the video - using the Urdu language of Pakistan rather than the Egyptian doctor Zawahiri's native Arabic - along with a new group spokesman identified as Usama Mahmoud.

The video is produced by Al-Qaeda's usual media arm, the As-Sahab Media Foundation - "The Cloud" - and SITE reported that it had been widely distributed on jihadist online forums.

'Policy statement'

Meanwhile the Pakistan Taliban has distanced itself from the recently formed splinter group Jamaat-ur-Ahrar and the Islamic State.

In a new "policy statement" released on Thursday, the Tehreek-e-Taliban Pakistan (TTP) spokesman Shahidullah Shahid termed both groups "suspicious" and "a conspiracy".

He said TTP has expelled its former Mohmand Agency commander Omar Khalid Khorasani or Abdul Wali, who founded the Jamaat-ur-Ahrar recently.

The Pakistan Taliban reiterated its allegiance to the Afghan Taliban and its leader, Mullah Muhammad Omar in a statement that comes on the same day as al-Qaeda announcing the formation of its new franchise in South Asia.