PESHAWAR: The death toll from a suicide bomb at a crowded mosque in northwestern Pakistan’s Khyber tribal region rose to 51 on Saturday, officials said.

A suicide bomber detonated himself as more than 500 people had packed into a mosque for Friday prayers in Jamrud town in the tribal district, killing many instantly and wounding scores more.

“The death toll has risen to 51 and 121 people were wounded,” local government official Khalid Mumtaz Kundi told AFP.

“Sixty-one of the wounded are still in hospital,” Kundi said.

Blood was splattered across the mosque's main hall and walls, while the building's doors and windows were destroyed and its ceiling fans mangled by the blast, according to an AFP reporter at the scene.

Ball bearings used in the suicide vest were also scattered across the mosque which lies 25 kilometres from Peshawar.

Friday's bomb was the deadliest since May 13 when two suicide bombers blew themselves up outside a police training centre in a town about 30 kilometres north of Peshawar, killing 98 people.

A little known militant spokesman who identified himself as Mohammad Talha claimed responsibility by telephone on behalf of the umbrella militant group Tehrik-i-Taliban Pakistan (TTP).

“We, the Taliban claim responsibility for this attack. This mosque belonged to KukiKhel tribe and we are fighting against them and anyone fighting with us will have the same fate,” Talha told AFP.

The authenticity of the claim could not be verified but bombings blamed on the Taliban and Al Qaeda-linked networks have killed more than 4,550 people since 2007, destabilising the state.