Officials say roadside bomb hit wedding party in Swat Valley.
Arshad Majid, the district police chief, said 40 bodies were accounted for, but the toll was expected to rise after forensic officials reconstruct body parts.
Another suicide bombing on Saturday killed one person and wounded 19 people, mostly security personnel, in the region, officials said.
The bomber struck a vehicle carrying security forces in the northwestern tribal region of Bajur, according to Iqbal Khatak, a government official.
He said the severed head of the attacker, who was on foot, was found at the scene.
All the victims were taken to a hospital where three of them were in critical condition, he said.
Immediately after Friday’s suicide bombing in Mingora, authorities made an emergency appeal for blood donations.
Syed Kamal Shah, health minister of the North West Frontier Province (NWFP), told the AFP news agency: “We are facing difficulty in the relief operation because the blast also damaged an electricity transformer in the area.”
He said the hospital facilities could not cope and there were not enough emergency supplies due to the ongoing military operation against armed groups in the area.
Pakistani troops have been battling Muslim fighters in the Swat valley, a once popular tourist site.
Major-General Nasser Janjua, a regional commanding officer, said earlier in the week that 400 fighters were hiding in the valley.
“Nobody has claimed the responsibility for the attack, but we suspect the involvement of miscreants (militants) against whom the military operation was being carried out,” another senior security official said.