At least 17 army soldiers were killed in a rebel attack in northeastern India on Thursday, police said.

The attackers were suspected to be from homegrown insurgent groups active in the restive region.

Eighteen soldiers were injured in what police said was a morning ambush in the Chandel district of Manipur state. The militants used bombs and guns in the assault, Manipur police Chief Shahid Ahmed told CNN.

One of the attackers is also believed to have died, he said.

Manipur is an impoverished, landlocked state in India’s remote northeastern belt. For years, many Manipuri tribal communities have resisted the authority of New Delhi, saying the central government has neglected them.