According to the army, the operation “Revenge” was carried out in response to “terrorist actions by illegal armed Armenian groups on the territory of Azerbaijan”.
Armenia is appealing to the world to take steps to stop what it calls “Azerbaijan’s aggressive actions,” according to a statement from the country’s foreign ministry.
Russia, which has 2,000 peacekeepers in the area, accuses Azerbaijan of breaking the ceasefire and says it intends to take steps to “stabilize the situation”.
The EU calls for an immediate end to hostilities.
“It is necessary to de-escalate, fully respect the ceasefire and return to the negotiating table to seek negotiated solutions,” reads a statement from the spokesperson for EU foreign affairs chief Josep Borrell.
Archenemies Armenia and Azerbaijan have waged war against each other twice, in the 1990s and in 2020, over Nagorno-Karabakh. The fighting in the fall of 2020 claimed over 6,500 lives and ended with a ceasefire that Russia helped negotiate.
Despite the ceasefire, tensions remain.