Sophisticated surveillance and tracking gadgets like thermal imagers and underground sensors have been installed along the porous Indo-Bangladesh border to prevent infiltration by Pakistan-backed terrorists.

The Border Security Force has been entrusted with installing the gadgets speedily along the 4,096-km frontier on the pattern adopted by the army along the 742-km Line of Control in Jammu and Kashmir [Images] and parts of the international border in Punjab and Rajasthan.

The BSF, which guards the Indo-Bangladesh border, has procured 900 hand-held thermal imagers and dispatched 400 of them to forward areas. The devices, which cost Rs 28 lakh each, can detect heat from the human body and will help track the movement of people, a senior BSF official told PTI.

Apart from this, the border force is in the process of installing Israeli-made long-range recce and observation system, a radar-based system capable of tracking moving vehicles or humans within a 40-km radius.

"We are in the process of procuring 27 such radars at a cost of Rs 2 crore each," the official said.

The introduction of the hi-tech gadgetry to stop infiltration comes close on the heels of revelations by security agencies that five of the 11 Pakistani terrorists responsible for the July 11 train bombings in Mumbai had entered the country from Bangladesh.