At least 16 people were killed and 40 others injured in a bomb blast at a crowded market in northwest Pakistan Saturday, security officials said.

Reports say the bomb attack occurred in the main market of the Darra Adam Khel town, near the Khyber tribal area. The market was crowded when the bomb went off, increasing the number of casualties. The injured, including two children, have been taken to hospitals in the nearby towns as the local health facilities couldn’t cope, the Tribune reported.

The death toll was expected to rise as several of the injured were in a critical stage, authorities said.

The blast happened in front of the “aman committee,” a peace committee office, belonging to a pro-government group of militants, who had earlier backed the Taliban but switched sides lately to support the local government, the BBC reported.

The initial reports stated that many of those killed were members of the peace committee.

At least 20 shops and several vehicles were damaged in the blast and authorities said no group had claimed responsibility for the incident thus far, Pakistan’s Dawn newspaper reported.

There are contradictory reports in the local media about how the bomb was triggered.

Some reports said that the bomb was detonated in a car while Reuters reported the blast was a suicide bombing.

The northwestern tribal belt of Pakistan has seen several incidents of attacks by the Taliban, and Pakistan’s military along with the support of the tribal leaders has been fighting the Taliban militia with limited success.

Pakistan’s government has been backing the ethnic tribal groups in the region and encouraging them to fight against the Taliban militants, as the Pakistan military, despite being one of the largest in the world, has not been able to rein in the unruly and lawless tribal groups supporting the hardcore extremists in the region. Several attacks between the government-supported militias and the Taliban-promoted militant groups, killing and injuring several people, were reported in the region in the past.