At least 80 people were injured, the Pak Tribune reported.

As much as 50 pounds of explosives detonated, Police Inspector Gen. Naveed Khan told Geo News. He said the crater left by the blast suggests that it was not a suicide attack.

An intelligence official said it appeared the bomber had intended to target minority Shia Muslims, but decided to detonate the bomb after being stopped by police in the Orakzai Agency, Dawn reported.

"The bomber tried to drive into a market in a Shia neighborhood ... but blew up his car when police tried to stop him at a checkpoint," the official said.

Security officials said a jirga, or tribal council meeting, was taking place near the site of the bombing. The jirga was aimed at settling hostilities between regional Shia and Sunni Muslims.

Dawn said a bombing of a tribal council in October killed more than 50 people.