The Border Security Force (BSF) has detected a tunnel just beneath the India-Pakistan international border fence in Jammu, officials said on Saturday.
The force has launched a major search operation in the area to look for other such hidden structures that aid infiltration even as it is analysing the spotted structure, they said.
BSF Director General Rakesh Asthana has directed his frontier commanders to ensure that the anti-infiltration grid is intact and there are no gaps along this front, they added.
The tunnel, about 50 metres from the border fence on the Indian side, was located by a BSF patrol on Thursday in the Samba sector of Jammu.
The force later examined the tunnel and found plastic sandbags on its mouth that had "Pakistani markings" on them, officials told PTI.
The tunnel, as per sources, has a depth of about 25 feet at the opening and the border force has launched a mega search operation along the IB in this area to detect any other such clandestine structure that can aid infiltrators to cross over from the Pakistan side and also help in smuggling of arms and narcotics.
About 8-10 plastic sandbags that have 'Karachi and Shakargarh' written on them have been recovered from the opening of the tunnel and the bags have a manufacturing and expiry date embossed on them indicating they were manufactured recently, officials said.
The nearest Pakistani border post is about 400 meters from the tunnel, they said.
The force has been conducting a mega 'anti-tunnel drive' in the IB areas of Jammu and other places after five armed infiltrators were recently killed by it along this front in Punjab.
The entire BSF formation deployed across the 3,300 km International Border that runs along Jammu, Punjab, Rajasthan and Gujarat is on extra alert as there are multiple intelligence inputs of terrorists trying to breach the IB and infiltrate into India, officials said.
The border force is also looking at deploying ground penetrating radars to detect tunnels along this sensitive front which is prone to infiltration from Pakistan and cross-border smuggling of arms and narcotics.
Tunnels have been detected by the BSF along the Jammu border front earlier too.