Image caption Factional infighting has increased since Taliban leader Hakimullah Mehsud was killed in November 2013

A split has emerged in the Pakistani Taliban after the major Mehsud faction walked out, saying the group leaders' tactics were "un-Islamic".

It is the first major rift in Pakistani Taliban ranks since 2007 when the umbrella group was first formed.

Analysts say the split may help advance peace talks with the government.

Tens of thousands of people have died in militant attacks in Pakistan in the last seven years, most of them claimed by the Taliban.

The rift comes after over a month of infighting in which dozens of fighters from the Tehreek-e-Taliban Pakistan (TTP) were killed.

The powerful faction comprising militants from the Mehsud tribe - the core around which regional militant groups initially gravitated to form the TTP - said it was forming its own separate group called Tehrik Taliban South Waziristan.

A spokesman for the new group, Azam Tariq Mehsud, told reporters the decision to part ways with the TTP was made when efforts to persuade the TTP leadership to give up practices which were "contrary to Islam" failed.

"We consider the bombing of public places, extortion and kidnappings un-Islamic, and since the TTP leaders continued with these practices, we decided we should not share the responsibility," he said.

Group 'weakened'

Differences within the TTP emerged when its founding leader, Baitullah Mehsud, was killed in a drone strike in 2009.

They came to a head in 2013 when Mr Mehsud's successor, Hakimullah Mehsud, was killed in another drone strike.

After Hakimullah Mehsud's killing, the leadership of the TTP passed to a non-Mehsud leader, Mullah Fazlullah, sparking internal rifts which have led to the present split.

The Pakistani government started peace talks with TTP in March, but officials say they are currently on hold because of Taliban infighting.

Media playback is unsupported on your device Media caption The BBC's Shahzeb Jillani said the group had been "turning its guns on each other"

Observers believe the split is going to leave the Taliban much weakened and prone to further defections by regional groups.

They say the development is likely to bring to the fore militant groups that are more amenable to peace talks with Pakistan.

With the secession of the Mehsuds, the TTP will now increasingly lean on the Swat and Mohmand factions, both actually based in north-eastern Afghanistan.

This means the TTP's centre of gravity is likely to shift from North Waziristan to tribal regions further north where the Taliban, though active, have largely been beaten and have bases in Afghanistan instead of in their native areas.