Azerbaijan has launched what it has called an “anti-terrorist operation” targeting Armenian military positions in the breakaway region of Nagorno-Karabakh, as heavy artillery firing was reported around its capital. The Azerbaijani defence ministry announced the start of the operation hours after four soldiers and two civilians died in landmine explosions in the Nagorno-Karabakh region. It raises concerns that a full-scale war over the region could resume between Azerbaijan and Armenia, which fought heavily for six weeks in 2020. 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”. The Azerbaijani statement said: “Only legitimate military targets are being incapacitated.” But ethnic Armenian officials in Nagorno-Karabakh said the region’s capital Stepanakert and other villages are “under intense shelling”. Earlier on Tuesday, Azerbaijan said six people died in two separate explosions in the region, which 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 highways 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 sizeable surrounding territories had been 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 which placed a Russian peacekeeper contingent in Nagorno-Karabakh. But 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 local officials said road connections to the region were not fully open. The hostilities come amid high tensions between Armenia and its longtime ally Russia. Armenia has repeatedly complained that the 3,000-strong Russian peacekeeping force was unable or unwilling to keep the road to Armenia open even though that duty was stipulated in the agreement that ended the 2020 war. Armenia also angered Russia, which maintains a military base in the country, by holding military exercises with the United States this month and by moving toward ratifying the Rome Convention that created the International Criminal Court, which has indicted Russian President Vladimir Putin. Russian foreign ministry spokeswoman Maria Zakharova on Tuesday denied claims that Russia was informed in advance of Azerbaijan‘s intention to mount the operation, saying the peacekeepers were notified only “a few minutes” before it began. Reporting by Associated Press.