Two officials of the Border Security Force were killed on Tuesday after militants allegedly ambushed them during patrolling in Tripura’s Dhalai district, PTI reported.

Members of the outlawed National Liberation Front of Tripura were allegedly involved in the attack.

The two BSF officers, identified as Sub-Inspector Bhuru Singh and Constable Raj Kumar, were posted on duty at the RC Nath Border Outpost under the Chawmanu police station of Dhalai district, the Hindustan Times quoted Tripura Police Deputy Inspector General (Law and Order) Arindam Nath as saying.

“After the incident, militants are likely to have crossed the India-Bangladesh international border,” Nath said.

The Dhalai district is about 94 km from state capital Agartala and it borders Bangladesh on the northern and southern sides.

The militants sustained injuries during the ambush, according to a statement by the Border Security Force Public Relations Officer from Frontier headquarters at Salbagan.

Tripura Chief Minister Biplab Kumar Deb condemned the attack and said that the “sacrifices of our brave security personnel shall not go in vain.”

The National Liberation Front of Tripura was formed on March 12, 1989, and has since then been split into multiple factions, The Indian Express reported.