NEW DELHI - Four soldiers were killed in a shooting at a military base in the Indian border state of Punjab early on Wednesday, the army said, and a search for the shooter was in progress.

The number of perpetrators was not known initially but it is now suspected that only one shooter was involved, a defence source told Reuters, declining to be named citing the sensitivity of the matter.

Four soldiers died from gunshot wounds 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.

There was no exchange of fire after the shooting and the base had been locked down to search for the shooter, the defence source said.

The incident was "not a terror attack", and took place in a canteen, a senior police official in Punjab, S.P.S. Parmar told Reuters.

The base was sealed off and a joint investigation with the local police was in progress, the army statement said, adding that no other injuries or 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.

(Additional reporting by Tanvi Mehta; Writing by Shilpa Jamkhandikar; Editing by Christian Schmollinger, Shri Navaratnam, Raju Gopalakrishnan, YP Rajesh)