Army troops discovered a 50-mt long tunnel near a forward post along the Indo-Pak border in Jammu region's sensitive Pallanwala sector which could have been used to infiltrate militants into India.

"On Aug 22 (yesterday), Army personnel during routine patrolling in Pallanwala sector found a tunnel approximately 50 metres long near the Chakla post on the Indian side of the Line of Control," he said.

"The tunnel is approximately two-and-a-half ft wide and three-and-a-half ft high and is leading towards the Pakistan Occupied Kashmir (PoK)," the spokesman said.

It appears to be an incomplete tunnel as no exit has been found on the Indian side, he said in a statement here. "Troops are carrying out thorough search of the area to ascertain further details which is taking time due to the existing minefield," the spokesman said.

The tunnel could have been used to infiltrate militants into the Indian territory, Army sources said.

The Army is strengthening its counter-infiltration grid to prevent any attempt by Pakistan Army to send ultras into India, the sources said.

Several senior officers including, Corps Commanders of the 15 and the 16 Corps, are constantly reviewing preparedness of troops on the ground, they said.

The tunnel is near the stretch where militants had made an infiltration bid on July 22 this year in which an ultra and a jawan were killed. Army troops had also detected a tunnel in same area in 2008.

On July 27, 2012, a cross-border tunnel was detected after earth caved in at two to three places due to rains near BSF's Chillayari Border Out Post (BOP) in Samba district of Jammu and Kashmir.