Border Guard Bangladesh in Bandarban's remote Thanchi upazila came under mortar shell attacks last night.

Six mortar shells were fired targeting the Bulu para BGB camp from Myanmar border around 10:00pm on Wednesday, said Col Habibur Rahman, BGB Bandarban sector commander.

In retaliation, the BGB fired two mortar shells, he said, adding that since the incident happened at night, “we could not trace the attackers”.

“The attackers might be members of law enforcement agencies of Myanmar or members of a separatist group, 'Arakan Army',” said the sector commander.

The BGB is investigating the matter and preparing a protest letter to be sent to the authorities on Myanmar side, he said.

The helipad of the camp inside the remote Sangu Reserve forest of the upazila was slightly damaged by the shelling, said Lt Col Reza of 57 BGB Battalion.

Additional forces of the BGB have been deployed at border points and patrols have been intensified, he added.

Meanwhile, tension is mounting at the border between Bangladesh and Myanmar, local people said.

BGB chief Maj Gen Aziz Ahmed said Bangladesh had expressed concern and conveyed a strong protest to the Myanmar Army and Myanmar Border Guard Police following the incident.

They have been warned that if any further shell is fired aiming at Border Operation Posts in Bangladesh, the BGB will retaliate and “they will have to take the responsibility for that," he told The Daily Star by phone.

"They, however, denied shelling. It has been assumed that the shells were not aimed at us," he said, adding those might have landed inside Bangladesh territory during a fight inside Myanmar against Arakan Army as the width of the bordering area is very narrow.

Replying to a query, the BGB boss, however, said this type of high transitory weapons is used by the Myanmar Army.

On August 26 last year, Myanmar's separatist group Arakan Army swooped on a BGB patrol team in remote Boro Modak area of Thanchi, leaving two border guards injured.