The attack took place Wednesday morning at the Bathinda military station in Punjab, a northern state where tensions have been high over the resurgence of a separatist movement.

India's military reported the attack on the morning it happened, saying four soldiers had been shot in their sleep, without giving further details or mentioning whether any attackers were still at large.

A police report quoting an army major who claimed to have witnessed the attack, seen by AFP Thursday, said two unidentified men had entered the highly guarded outpost with their faces covered.

One was carrying a rifle reported missing from the base two days earlier, the report said, and the duo fled towards a forest near the barracks after the attack.

Police were scanning CCTV footage and a search for the suspects was underway, local media reports said Thursday.

Another soldier was found dead by apparent suicide at the same military station on the same day as the attack, but there was no connection with Wednesday's shooting, the army said in a statement.

Punjab has been on edge since authorities launched a manhunt for firebrand Sikh separatist preacher Amritpal Singh last month.

Singh has rallied a huge following in recent months by demanding the creation of Khalistan, a separate Sikh homeland, the struggle for which sparked deadly violence in Punjab in the 1980s and 1990s.

He remains at large despite a huge dragnet involving thousands of police officers and a statewide internet shutdown that lasted for several days.