The defense ministry of Azarbaijan on Tuesday says it has begun "anti-terrorist" operations in its breakaway region of Nagorno-Karabakh that’s under Armenian control now.
Tensions have been high for months surrounding the ethnic Armenian enclave, recognized internationally as part of Azerbaijan, reports BBC.
Eleven Azerbaijani police and civilians have been reported killed in a mine blast and another incident.
Air raid sirens have been reported in Karabakh's main city.
Defence officials in the breakaway region said the Azerbaijani military had "violated the ceasefire along the entire line of contact with missile-artillery strikes". Other Karabakh representatives spoke of a "large-scale military offensive".
The two neighbours, Azerbaijan and Armenia, have gone to war twice over Nagorno-Karabakh, first in the early 1990s after the fall of the Soviet Union and again in 2020.
Since December, Azerbaijan has mounted a de facto blockade of the only route into the enclave from Armenia, known as the Lachin Corridor.
On Tuesday, the defence ministry in Baku accused Armenian forces of "systematic shelling" of army positions and said it had responded by launching "local, anti-terrorist activities... to disarm and secure the withdrawal of formations of Armenia's armed forces from our territories".
It insisted it was not targeting civilians or civilian facilities, but instead said "only legitimate military targets are being incapacitated by the use of high-precision weapons".
Armenia's defence ministry said the claims of Armenian fire did not correspond with reality.
The sound of artillery and gunfire could be heard on Tuesday from the Karabakh regional capital Khankendi, known as Stepanakert by Armenians. An estimated 120,000 ethnic Armenians live in the mountainous enclave.
Officials in Armenia added that as of 14:00 (10:00 GMT), the situation on the country's borders was "relatively stable".
In a statement, Russia urged both countries to respect a ceasefire signed after the war in 2020. The EU's regional special representative Toivo Klaar said there was "urgent need for immediate ceasefire".
During that six-week conflict, Azerbaijan recaptured territories surrounding Karabakh that had been held by Armenia since 1994.
A fragile ceasefire policed by some 3,000 Russian peacekeepers has since come under increased pressure, with Moscow's attention diverted by its full-scale invasion of Ukraine. Armenian Prime Minister Nikol Pashinyan recently said Russia was "spontaneously leaving the region".
Azerbaijan had denied building up troops numbers in the region and on Monday allowed aid from the International Committee of the Red Cross into Karabakh on two roads, one via the Lachin Corridor from Armenia and the other on Azerbaijan's Aghdam road.
Bd-pratidin English/Lutful Hoque
