Islamabad, Pakistan (CNN) -- A bomb exploded near a market in northwest Pakistan on Saturday, killing at least 25 people and injuring 40, government official Khalid Mumtaz said.
The bomb was in a truck in Landi Kotal town in Khyber, a district in Pakistan's tribal region, according to two other local officials, Arshad Khan and Gulam Faruq.
It targeted members of Zakha Khel tribe, a pro-government group locked in a bloody turf war with militant group Lashkar-e-Islam.
For years, the militant group has fought for dominance in the district by taking on both the Pakistani Taliban and government forces.
Khyber is one of seven districts in Pakistan's mostly ungoverned tribal region along the Afghan border. The area has been plagued by a mixture of sectarian and gang violence, as well as the government's fight to take on the region's Islamist militants.
One of NATO's main supply routes in Pakistan went through Khyber until the Pakistani government shut it down last year in protest over a NATO strike that unintentionally killed 24 Pakistani soldiers.
Journalist Aamir Iqbal contributed to this report.