PESHAWAR, Pakistan - Witnesses and officials say at least 40 people are dead after a suicide bomber blew himself up at a peacemaking meeting of tribal elders in northwestern Pakistan.

It was the third suicide bombing in as many days in the northwest, where security forces were battling pro-Taliban Islamic militants.

It took place at the public meeting in the town of Darra Adam Khel about 40 kilometres south of the provincial capital, Peshawar.

Dr. Hamid Afridy, the area's chief medical officer, said he counted 40 bodies at the scene, some with severed limbs and mutilated faces.

He says more than 100 injured have been sent to hospitals in Peshawar and a nearby town.

He fears the death toll could rise because many of the injured were in critical condition.

"It was a huge explosion and left body parts and blood scattered on the ground," said Ramin Khan, whose left leg and face were wounded.

State-run Pakistan Television said the suspected bomber's severed head was found.

Television footage showed blood, shoes and caps littering the bombing site - a tree-lined ground amid wheat fields that is only a few yards away from brick homes.

Darra Adam Khel resident Saeed Khan was near the site and said thousands of people from five tribes were meeting in the open area when the blast went off.

On Friday, a suicide bomber blew himself up at the funeral of a slain police officer in Mingora town in Swat Valley, killing more than 40 people and injuring at least 60. The next, day another suicide bombing in nearby Bajur killed one person and wounded 19 others, mostly security personnel.