Four soldiers were killed in firing at a military base in the Indian border state of Punjab early on Wednesday, the army said, and a search for the shooters was in progress.

An unknown number of shooters were at large at the base in Bathinda city, a defence source told Reuters, declining to be named citing the sensitivity of the matter.

Four soldiers succumbed to gunshot injuries sustained during the firing incident, which took place in the early hours of Wednesday morning, an army statement said. The statement did not mention the circumstances or other details about who was responsible for the incident.

The incident was “not a terror attack”, and took place in a canteen, a senior police official in Punjab, SPS Parmar told Reuters.

The base was sealed off and a joint investigation with the local police was on, the army statement said, adding that no other injuries and damage to property was reported.

“All aspects including the possible case of involvement of an (assault) rifle along with 28 rounds reported missing two days back are being ascertained,” the army said.

Visuals from Reuters partner ANI showed barricades placed on the road outside the gates of the military station and security personnel deployed outside the boundary wall.

The incident took place at 4:35 a.m. (2305 GMT Tuesday), an earlier army statement said.

The military base, about 280 km (175 miles) northwest of New Delhi, houses mostly families of soldiers. The border with Pakistan is about 100 km (62 miles) west of Bathinda.