"They are definitely Pakistani, but unless we examine the documents we cannot come to any conclusion (about LeT links)," Lal said.

"The team asked the men to surrender but they fired at the Indian officers, and they were shot in a fierce 30-minute gun battle in a nearby field," Lal added.

One officer was injured in the crossfire.

Arms haul

Police said they found two AK-47 assault rifles, five hand grenades and detonators in the car.

The incident occurred on the eve of the Indian Republic Day, to be celebrated amid heightened security.

Fears that armed groups could disrupt the annual military parade have led to the deployment of 20,000 heavily armed troops, Delhi police said.

YS Dadwal, New Delhi's police commissioner, said there were "intelligence inputs" that Islamist groups may be planning to attack the Republic Day parade, which is designed to display India's role as a regional economic and military power.

On January 26, 1950, India became a sovereign democratic state with a written constitution and an elected parliament, after gaining independence from British rule in 1947.