More than 40 vulnerable unfenced stretches along the India-Pakistan border will be covered by laser walls soon with the Home Ministry giving it a top priority to check any infiltration of terrorists in the wake of the Pathankot attack.

All these riverine stretches located in Punjab will be covered by the laser wall technology developed by Border Security Force to completely eliminate the chances of breach of the international border by Pakistan-based terror groups, a Home Ministry official said.

A laser wall is a mechanism to detect objects passing the line of sight between the laser source and the detector. A laser beam over a river sets off a loud siren in case of a breach.

As of now, only 5-6 out of around 40 vulnerable points are covered by laser walls. This beam over the river sets off a loud siren in the case of a breach.

The suspected infiltration point of Ujj river in Bamiyal used by the six Jaish-e-Mohammad terrorists before storming the Pathankot air base was not covered by a laser wall.

A camera to keep watch over the 130-metre-wide river bed was found to be not recording the footage.

BSF has covered this stretch by putting up a laser wall last week before Prime Minister Narendra Modi's visit to Pathankot air base on January 9.

The border guarding force had started putting up laser walls on unfenced riverine stretches of international border last year in Jammu sector, which was more prone to terrorist intrusions till three terrorists carried out attack in Gurdaspur in Punjab in July last year.

The terrorists believed to have entered India five kms downstream of Bamiyal near the Tash border outpost - a riverine point not covered by a laser wall as well.

Bamiyal has BSF posts on either side of the river with a personnel on each post keeping a watch on the river round the clock. The area is also lit up with high mast lights.

There is a possibility that the six JeM terrorists might have walked through the dry river bed at night and BSF personnel might have missed them.

Officials said Bamiyal is not known as a drug trafficking route as no drugs have been seized here over the past 3-4 years.

The BSF has already deployed additional personnel along the border in Punjab and boat patrolling has been intensified, particularly during night.