A BSF jawan lost his hand and sustained grievous injuries after Bangladeshi cattle smugglers attacked him with bombs in the early hours of Thursday along the India-Bangladesh border in West Bengal, the force said.

Constable Anisur Rehman also suffered pellet injuries to his lungs, liver and stomach from the impact of at least two country-made bombs lobbed at him near the Angrail border post in the North 24 Parganas district at about 3:30 am.

In the wake of the incident, the Border Security Force (BSF) issued an alert along the India-Bangladesh border in the south Bengal area as it registered a "strong protest" with their counterparts, the Border Guards Bangladesh (BGB) to rein in the criminals on their side.

The jawan on border duty was attacked by a group of about 25 Bangladeshi smugglers who entered 200 metres into the Indian side in order to smuggle cattle into their country with the assistance of locals here, the force said.

The smugglers were armed with bombs, dahs (cleaver-shaped weapon), axes, bamboo sticks among others, it said.

They encircled the jawan and hurled two country-made bombs on him. He was evacuated to the government hospital in Bangaon where his right hand was amputated.

"The jawan has suffered grievous injuries and he fired a round from his pump action gun in self defence before he fell unconscious. Reinforcement troops controlled the situation.

"The smugglers escaped to the other side as it was pitch dark and the area is marked with heavy vegetation and tall grass growth," a senior official said.

A smuggler is also suspected to have been injured in the firing by the jawan, he said.

The BSF has directed all its formations in the south Bengal frontier area "to adopt an aggressive posture against trans-border criminals and thwart their sinister designs. Such incidents of attacks on BSF troops are taking place quite often," the force said.

On Wednesday, the border guarding force had repulsed an attack by about 200 Bangladeshi cattle smugglers and seized 107 buffaloes along the Indo-Bangla border in Murshidabad district of the state.