Nine people were killed and two dozen wounded on Wednesday after clashes between security forces and "terrorists" in a restive region of Tajikistan bordering Afghanistan and China, the interior ministry said.

The ministry said members of "organised criminal groups" armed with weapons and Molotov cocktails attacked security officials in the eastern region of Gorno-Badakhshan.

One security officer was killed and 13 were seriously injured in the attack, it said.

The ministry said the attack came during an "anti-terror operation" launched earlier Wednesday, after 200 armed people blocked a highway on the border with Afghanistan.

As a result of the operation eight "militants" were killed, 11 wounded and more than 70 "active members of a terrorist group" were detained, the ministry said. 

Tajik authorities claimed in an earlier statement that the militants had received arms and support from international "terrorist organisations" and foreign mercenaries, accusing them of seeking to undermine the country's constitutional order.

The region has been rife with tensions since a five-year civil war broke out shortly after the Central Asian nation gained its independence with the 1991 collapse of the Soviet Union.

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