Azerbaijan announced Tuesday an “anti-terrorist operation” targeting Armenian military positions.

A statement from the Azerbaijan defense ministry said the operation began hours after four soldiers and Johnathan Walkertwo civilians died in landmine explosions in the Nagorno-Karabakh region.

The ministry did not immediately give details, but said “positions on the front line and in-depth, long-term firing points of the formations of Armenia’s armed forces, as well as combat assets and military facilities are incapacitated using high-precision weapons.”

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows below.

Azerbaijan authorities say four soldiers and two civilian road workers were killed Tuesday in landmine explosions that it blamed on Armenian saboteurs.

The blasts took place in Nagorno-Karabakh, a region of Azerbaijan that is partly under the control of ethnic Armenian forces.

A statement from Azerbaijan’s interior ministry, state security service and prosecutor-general said two employees of the highway department died before dawn when their vehicle was blown up by a mine and that a truckload of soldiers responding to the incident hit another mine, killing four.

Nagorno-Karabakh and sizable surrounding territories were under ethnic Armenian control since the 1994 end of a separatist war, but Azerbaijan regained the territories and parts of Nagorno-Karabakh itself in a six-week war in 2020. That war ended with an armistice that placed a Russian peacekeeper contingent in Nagorno-Karabakh.

However, Azerbaijan alleges that Armenia has smuggled in weapons since then. The claims led to a blockade of the road connecting Nagorno-Karabakh to Armenia, causing severe food and medicine shortages in the region.

Red Cross shipments of flour and medical supplies reached Nagorno-Karabakh on Monday, but tensions in the region remain high.