"Some of the dead were shot and some had their throats slit," Marwat said.
During clashes earlier this week in Jandola, Taliban fighters captured about 27 people belonging to the peace committee and local tribal elders, he said.
Security officials said that the men's hands were tied behind their backs and the corpses left in a drain by a roadside.
'Reign of terror'
A spokesman for the Tehreek-e-Taliban Pakistan controlled by Mehsud, told the AFP news agency that it had carried out the killings and would soon decide the fate of another eight men.
"The men we killed were involved in thefts and robbery and had unleashed a reign of terror on the people. They were being patronised by the government," Maulvi Omar said.
"The government should not intervene in the current situation, otherwise peace talks would be seriously undermined."
Fighting between supporters of a pro-government tribal elder, called Turkistan Bitani, and fighters belonging to Mehsud's tribe broke out on Monday after rockets were fired at the home of a peace committee member.
Kamal Hyder, Al Jazeera's correspondent in Islamabad, said the attacks came as pro-Taliban forces continue to tighten their grip in the region, espcially in the Northwest Frontier Province (NWFP).
"A lot of analysts believe that Peshawar is being surrounded by pro-Taliban factions. That is why the interior minister went there and warned people that the government could launch an operation in the Northwest Frontier Province."
Pakistan's military put the overall death toll from the violence at nine, and said that the Taliban fighters had withdrawn from Jandola.
"There is absolutely nothing now in Jandola. A total of nine people have been killed in fighting between tribes," Major General Athar Abbas, Pakistan's chief military spokesman, said.
But residents told the AFP news agency that the situation in Jandola was still tense and armed fighters were still present. All shops were closed down and roads were deserted, they said.
Pakistan's government began peace talks with Mehsud, who is based in the South Waziristan tribal region, after defeating supporters of Pervez Musharraf, the president, in elections in February.
Pakistan's border regions have been the scene of fighting between troops and pro-Taliban fighters since the fall of the movement in neighbouring Afghanistan in 2001.
There have also been several outbreaks of violence between the area's Pashtun tribes.