Azerbaijan’s launch of reportedly intense artillery fire in the Nagorno-Karabakh region on Tuesday raised fears that another full-scale conflict with Armenia could be under way, less than three years after a war that killed more than 6,000 people there.

Nagorno-Karabakh, with a population of about 120,000, is an ethnic Armenian region of Azerbaijan that has been a flashpoint since the collapse of the Soviet Union.

The region and sizable surrounding territories came under the control of ethnic Armenian forces backed by the Armenian military at the 1994 end of a separatist war.

Azerbaijan regained the territories and parts of Nagorno-Karabakh itself in fighting in 2020.

The latter war ended with an agreement to deploy Russian peacekeepers in the region, but tensions have soared since December when Azerbaijan began blocking a road that connects Nagorno-Karabakh with Armenia proper.

The artillery firing that Azerbaijan calls an “anti-terrorist operation” started hours after it said four soldiers and two civilians were killed by landmines that it said were planted by Armenian saboteurs.