DHAKA, Bangladesh (AP) — Six people were killed in a gunfight Tuesday between two factions of an ethnic group over control of a hilly region in southeastern Bangladesh where armed gangs are active, police said.

The clash took place between Parbatya Chattogram Jana Sanghati Samiti and its reformist faction, both dominated by the influential Chakma tribe in Bandarban district, police official Mobasser Hossain said. He said all of the dead were from the reformist faction.

The group previously fought an insurgency against Bangladesh’s military and other security agencies for decades with India’s help, demanding greater autonomy for a region known as Chittagong Hill Tracts. The insurgency ended after the group signed a peace treaty with the government in 1997, but some group members were unhappy because they wanted more political freedom for the ethnic group.

Bandarban is 387 kilometers (240 miles) southeast of Dhaka. About a dozen ethnic groups live in the region. Each has its own dialect, distinctive dress and rituals.

Hossain said the bodies were being taken to a police station and police have launched an investigation.

Such attacks are common in the region because some of the groups are reportedly involved in illegal activities such as drug trafficking and kidnapping for ransom.