A bomb killed at least 23 people and wounded 26 on Tuesday when it exploded near a fuel station in Pakistan's northwestern Khyber region.
"It was a huge blast and caused damage to a number of vehicles at (a) bus terminal," said Khyber tribesman Khan Zaman from the Jamrud bazaar, around 25 km (15 miles) west of the city of Peshawar.
Tribesman said members of the pro-government Zakhakhel tribal militia were the target of the attack. Members of the militia -- or "lashkar" -- were filling their vehicles at the station when the bomb exploded.
Assistant Political Agent Jamrud Mohammad Jamil Khan said three members of the Khasadar tribal police force were killed. The wounded were taken to hospitals in Jamrud and Peshawar.
Officials said there had been no claim of responsibility yet for the attack.
Pakistani forces have targeted militants in Khyber, including the Pakistani Taliban, on and off for more than four years.
Tuesday's bombing is the first major one of its kind this year. On Dec. 30, 13 people were killed in a bombing in the southwestern city of Quetta.
The attack also comes amid conflicting reports of peace talks between the Tehrik-e-Taliban Pakistan (TTP) and the Pakistani government.
The TTP, formed in 2007 and allied with the Afghan Taliban, is an umbrella group of various militant organisations entrenched in Pakistan's unruly tribal areas along the porous frontier with Afghanistan.
It has pledged to overthrow the Pakistani government after the military started operations against the militants in 2007.