The toll from a suicide bombing on a mosque packed with worshippers rose to 68 on Saturday, as four others died in an attack nearby, ending a lull in violence in Pakistan's militant-riddled northwest.
In the country's deadliest attack in two months a mosque was reduced to blood-spattered rubble strewn with body parts after a suicide bomber detonated explosives as worshippers attended Friday prayers.
The blast, which occurred in the Darra Adem Khel region, was followed hours later by a grenade assault on a second mosque in the same area, which killed at least four people.
"Sixty-eight people are now confirmed dead in the mosque suicide bombing," top local administration official Shahidullah told AFP.
The official said the death toll might rise after many people took away the bodies of their loved ones from the site of the attack so those were not included in the grim counting process.
Dozens were critically wounded and officials fear the toll from both attacks could rise.
Suspicion quickly turned to Islamist militants known to operate in the restive region which is on the front line of the US-led war on al Qaeda.
Khalid Umarzai, a regional administrator, suggested the attack could have been retaliation for military operations targeting against them.
"An operation is going on by the army and Frontier Corps (paramilitary) in the Darra Adam Khel area. We had been expecting such attacks," he said.
The first explosion turned worship into a bloodbath in Akhurwall village, part of the semi-tribal northwest area of Darra Adam Khel, about 140 kilometres (90 miles) west of the Pakistani capital Islamabad.
Eleven children were among the dead, said a local official.
Only one wall was left standing and the concrete roof collapsed, leaving bloodstains, human remains and hair scattered in the debris.
Houses near the mosque were also damaged, including that of Wali Mohammad, the leader of a pro-government militia that had clashed repeatedly with local Taliban militants until reportedly cutting a deal earlier this year.
Although the Taliban denied responsibility, a local elder blamed the group, suggesting it could have been acting to punish Mohammad's militia.
Witnesses said the bomber walked into the mosque and shouted "Allahu akbar" (God is greater) before a deafening explosion.
Dilawar Gul, 30, said he was collecting donations from worshippers when he heard the suicide bomber shout.
"Then I heard a huge blast which flung me to part of the mosque where the roof didn't collapse, and I survived."
Local administration official Gul Jamal Khan told AFP that 61 people had been killed and 104 wounded.
Local elder Sohbat Khan Afridi blamed the Taliban, saying Mohammad, who formed his tribal militia in 2007 to fight the militants, has a house close to the mosque, although he is understood to live in Lahore.
The Taliban and the militia, which is known locally as a lashkar, clashed repeatedly in the area but this year reached a compromise in which blood money was paid to the Taliban, Afridi said.
But Azam Tariq, spokesman for Pakistan's Tehreek-e-Taliban, denied that the faction was involved. The Taliban routinely deny attacks that kill civilians but have been blamed for some of the country's most devastating bombings.
At least four more people were killed and 14 others wounded when hand grenades were thrown into a mosque in the second attack 20 kilometres (12 miles) away, a hospital official said.
United Nations chief Ban Ki-moon, the European Union and the United States condemned the attacks, with Washington saying they had "brutally targeted innocent people" at places of worship.
Ban Ki-moon "is dismayed by the indiscriminate killing of civilians in a place of worship, which no cause can justify," his spokesman said.
Around 3,800 people have been killed in suicide attacks and bombings, blamed on homegrown Taliban and other Islamist extremist networks, since government troops stormed a radical mosque in Islamabad three years ago.
The United States wants Pakistan to do more to fight insurgents crossing into Afghanistan and fuelling a nine-year Taliban uprising there.
Friday's bombing was the deadliest in Pakistan since a suicide attacker slaughtered 60 people at a Shiite Muslim rally in the southwestern city of Quetta on September 3.