Attackers wearing military uniforms shot dead 12 people and wounded 15 on Friday in a busy market area in a town in India's restive northeastern state of Assam, in an attack blamed by the authorities on a regional separatist group.

Six rebels arrived in a motorised rickshaw and fired automatic weapons and lobbed grenades in the crowded market in Balajan, an area just outside the town of Kokrajhar in western Assam, said top local police official L.R. Bishnoi.

He said that one gunman was killed by security forces and troops were pursuing five others who fled.

Several homes and shops were badly damaged in the attack.

A senior home ministry official in New Delhi said preliminary reports indicated the attack was carried out by separatist militants of the National Democratic Front of Bodoland (Songbijit).

“Police have launched a hunt to trace insurgents hiding near the incident spot. It is a militant attack and we will be sending a team from Delhi to investigate further,” the official said.

“This attack is intended to destabilise peace in Assam,” said Himanta Biswa Sarma, the state's finance and health minister. There was no claim of responsibility for the attack.

The attack took place in a remote part of Assam near the border with Bhutan that is home to the indigenous Bodo people, who have for decades waged a violent campaign for a separate homeland.