The attacker blew himself up at Pasht bazaar in the northwestern Salarzai region, some 35 kilometres (20 miles) from Khar, the main town of the restive Bajaur tribal district, which borders Afghanistan.
Earlier the officials had said a timed bomb exploded.
"Initially it looked like a bomb blast, but later investigators found out that it was a suicide bombing and the body of the attacker was also found," local government official Saad Mohammad told AFP.
"Eight people were killed and 11 others were wounded in the attack," he added.
Health department official Khan Saeed said that condition of three of the wounded was critical.
"Two tribal elders, Malik Tehsil Khan and Malik Mayn Jan also died in the bomb blast," local government official Irshad Khan told AFP.
"We think that they were the main targets because they were the senior members of local peace committee which has formed a lashkar (tribal force) against the Taliban," he added.
Taliban militants, who have targeted members of the pro-government Salarzai tribe in the past because they raised a village force to drive them out of region, claimed responsibility for the suicide attack.
"We carried out the bombing against the peace committee because they had joined the government and were maligning the Taliban," Tehreek-e-Taliban spokesman Ehsanullah Ehsan told AFP.
"We had warned them before and warn them again that they should disband this anti-Taliban peace committee otherwise we will continue to attack them till they are totally eliminated," Ehsan said.
In Pakistan's first known female suicide attack, a woman wearing a bomb under her burqa struck near a UN food distribution point in Khar on December 25 killing 43 people. The Salarzai tribe was again the target.
Pakistani security forces have carried out a series of military operations against the Taliban and other Islamist militants in Bajaur since August 2008. The military has claimed repeatedly to have eliminated the militant threat.
Bajaur is one of seven districts in Pakistan's semi-autonomous tribal belt on the Afghan border. The United States considers the area the global headquarters of Al-Qaeda and the most dangerous place on earth.
More than 4,400 people have been killed across Pakistan in attacks blamed on Taliban and other Islamist extremist networks based in the tribal belt since government troops stormed a radical mosque in Islamabad in 2007.