Umar Khalid, leader of the Pakistani Taliban in the Mohmand tribal area, told CNN that local people had been warned against joining the government side. "We will continue to attack all pro-government officials and their supporters," he said.
In what appeared to be a suicide attack, the bombers struck a local administration compound in Ghalalnai, near the Afghan border, Geo News reported.
More than 100 people were thought to have been inside the compound, where government officials, tribal elders and anti-Taliban militia members were meeting, officials said.
Among those killed was Haji Kachkol Khan, a senior leader of the local "peace committee," said Shamas Ul Islam, another government official.