New Delhi: A soldier of the 18 Sikh regiment shot dead two of his colleagues before killing himself with his service INSAS rifle in Himachal Pradesh's Dharamshala cantonment in the wee hours on Monday.

Sources in the army headquarters said Jasbir Singh, who was on guard duty, had an argument with the other two soldiers and fired at his two colleagues who were about to sleep. The victims were identified as Havildar Hardeep Singh and Naik Harpal Singh. All the three soldiers died on the spot.

A statement, issued by the army said: "In an unfortunate incident at 2.30 am a soldier shot two other personnel from his unit & thereafter shot himself. Jasbir had six months of service in the unit. Incident occurred in the 18 Sikh regiment, Dharamshala cantonment."

A preliminary probe by the army revealed that Jasbir, apparently in a fit of rage, shot them and later turned the gun on himself after a verbal duel with them.

Jasbir hailed from Barnala in Punjab while Hardeep Singh and Harpal Singh were from Gurdaspur.

"The reason for the provocation is still not known. A court of inquiry has been ordered," said an army official.