Tajikistan has launched an “anti-terror operation” in a restive region that borders Afghanistan and China and has long been a flashpoint of tensions, police said on Wednesday.

The interior ministry said some 200 “members of an organised criminal group” blocked a highway in the eastern region of Gorno-Badakhshan on the border with Afghanistan linking Tajikistan and China “in order to destabilise the social and political situation.”

The same groups attacked a security convoy with firearms and petrol bombs, the ministry said, killing the officer and wounding 13 other troops. Security forces killed eight attackers and detained more than 70 people.

“Law enforcement agencies have begun an anti-terror operation,” the interior ministry said in a statement carried by state news agency Khovar.

Tajik authorities claimed that the militants had received arms and support from international “terrorist organisations” and foreign mercenaries and accused them of seeking to undermine the country’s constitutional order.

“The organised criminal groups did not comply with the lawful demands of law enforcement officers to hand over their weapons and ammunition and put-up armed resistance,” the interior ministry said. Authorities provided no other details.

Tensions between the government and residents of the nominally autonomous eastern region have simmered ever since a five-year civil war broke out shortly after the collapse of the Soviet Union in 1991.

A linguistically and ethnically distinct region, Gorno-Badakhshan has been home to rebels who opposed government forces during the conflict.