A Border Security Force (BSF) jawan was killed and another injured on Thursday after a Bangladeshi border guard fired from his AK-47 rifle during a 'flag meeting' along the international border of the two countries in West Bengal, officials said.

The "apparent high handedness" of the Border Guard Bangladesh (BGB) troops has led to tension between the two sides with BSF chief V K Johri calling up his counterpart Major General Shafeenul Islam over a hotline.

The BGB Director General has assured a through probe of the incident, they said.

The relations between the two forces have been very cordial and no bullet has been fired between them for decades. This incident is an aberration and efforts are being made to ensure that the situation does not deteriorate, official sources said.

The incident has rung an alarm in the top security establishment in New Delhi with the Union home ministry and ministry of external affairs being briefed by the BSF.

Officials said the incident took place under the Kakmarichar border post of the BSF in Murshidabad district about 9 am when a force party approached BGB personnel, standing at a "char" or a riverine in the middle of the Padma river, to resolve an issue linked to Indian fishermen.

They said the trouble started when the BGB personnel held three Indian fishermen who were allowed by the BSF to fish within the International Border, that runs through the middle of the 3-km-wide Padma river.

The river offers a rich catch of the hilsa fish.

A BGB team then allowed two fishermen to go and inform the BSF that the third person has been held by them and that was when the BSF post commander of the 117th battalion, a sub-inspector, took a six-member party on a motor-boat to resolve the issue.

A BGB jawan identified as Sayed fired from behind when the six-member BSF party started to return back on their motor-boat after seeing "aggressiveness" of the Bangladeshi personnel.

The BGB trooper, they said, fired from his AK-47 rifle and shot BSF head constable Vijay Bhan Singh on his head, while constable Rajvir Yadav sustained bullet injury on his hand.

The BSF jawan died on the boat itself and injured constable Yadav deftly saved the boat from drowning and brought it safely to the Indian side.

Security has been stepped up all along the 4,096-km Indo-Bangla border in the wake of the incident.