A suicide bomber has struck a mosque frequented by anti-Taliban tribal elders in northwestern Pakistan during afternoon prayers, killing at least 67 people in one of the deadliest attacks this year.Later on Friday, three grenade blasts killed three people at a mosque in another northwest area where an anti-Taliban militia was active.GEO News TV reported that the Pakistani Taliban claimed responsibility for the attack, but the group's spokesmen did not immediately respond to calls from The Associated Press seeking comment.Another local government official, Saeed Khan, put the death toll at 67 and said 100 others were wounded. That made the attack the deadliest since a pair of suicide bombers killed 102 people and wounded 168 in the Mohmand tribal region in July.In the first attack, the bomber struck while on Friday prayers were underway in the mosque at Attariwal village in Akhorwal area, 45 km south of Khyber-Pakhtunkhwa capital Peshawar.Part of the mosque's ceiling collapsed and people were buried under the debris, officials said.The death toll could rise as many of the injured are in a critical condition, Kohat district administration chief Shahidullah Khan said.Officials said the bomber was a youth aged about 17 or 18 years who managed to enter the mosque, located near the 'hujra' (guest house) of pro-government tribal elder Malik Wali Khan.An official Shahidullah Khan said authorities received warnings about such attacks almost on a daily basis.Kohat Commissioner Khalid Umarzai told the media that authorities were expecting such attacks due to operations being conducted by security forces against the Taliban in Darra Adam Khel and nearby tribal areas.The local chapter of the banned Tehrik-e-Taliban Pakistan claimed responsibility for the attack. Tribal elder Malik Wali Khan had formed a 'lashkar' or anti-Taliban militia in 2008 to crush militants in the area.However, he later agreed to patch up with the rebels after making a payment to the Taliban, sources said.Khan then shifted to Lahore and began living there. Witnesses said the blast occurred as the Imam was delivering the sermon to worshipers sitting in rows.They said they had seen blood and human flesh spattered all over the mosque. Officials said the bomber's suicide vest contained 10 to 15 kg of explosives.

Many of the bodies and injured were taken to the state-run Lady Reading Hospital in Peshawar, where authorities declared an emergency.Officials at the hospital said two children were among the bodies they had received. Several children were also among the injured, they said.