* Fazlullah sacks top commander to stop tribal infighting
* Commander fighting for control of powerful Mehsud tribe
* Chief turns to influential hardliner to find solution
By Jibran Ahmad
PESHAWAR, Pakistan May 10 (Reuters) - The head of the Pakistani Taliban is making a last-ditch bid to stamp his authority on the increasingly divided insurgency by ordering a top commander sacked, Taliban sources said Saturday.
Taliban head Maulana Fazlullah moved against Khan "Sajna" Said on Friday after weeks of bloody infighting in the powerful Mehsud tribe that supplies the bulk of the Pakistani Taliban fighters, they said. Scores of men have been killed.
The risk for Fazlullah is that Said might ignore him and battle on. Said is trying to wrest control of the Mehsud tribe - with its many weapons and lucrative smuggling routes and extortion business - from rival Shehryar Mehsud.
The factional fighting has complicated attempts by the Pakistani government to end the insurgency through peace talks it proposed in February. Some commanders are in favour of talks but others vowed to continue their insurgency.
"It's a test case for Maulana Fazlullah and his shura," a Taliban commander said, referring to the movement's leadership council. "It will determine their future."
"If Sajna is convinced and he stops fighting, it conveys a good message to rest of the Taliban factions," he said. "Otherwise it will be a setback for Fazlullah if Sajna refuses to obey his command."
Fazlullah has repeatedly appealed in vain to the two Mehsud rivals to stop fighting. An earlier peace deal brokered by the powerful Haqqani network of fighters fell through, undercutting the militants' ability to mount attacks against security forces.
Notorious for ordering the attempted killing of schoolgirl activist Malala Yousafzai, Fazlullah is the first non-Mehsud leader of the Pakistani Taliban and has struggled to impose his authority on the powerful tribe.
He faced many challengers to become chief of the Pakistani Taliban last year after the death of the previous head in a drone strike. He has been hiding in Afghanistan since then.
But the time has come to exert his authority, a senior member of the Taliban said.
"Senior members of Tehrik-e-Taliban Pakistan had tired of appealing (to the two rivals) to stop their clashes," he said.
The Taliban sources said Fazlullah turned to an influential hardline commander, Khalid Omar Khorasani, to appoint a new commander in place of Said, who wants to join the peace talks.
Khorasani, who opposes the talks, ordered the decapitation of 23 hostages from a government paramilitary force shortly after Islamabad announced its peace initiative.
Taliban commanders said Khorasani had been chosen to appoint a successor not just because of his hardline reputation, but because of his ability to unite various factions.
"All militant leaders respect him for his sacrifices in organising all the militant factions and that's why Fazlullah gave him this difficult task," a Taliban commander said. (Writing by Katharine Houreld; Editing by Tom Heneghan)