Azerbaijan says it shelled Sotk in retaliation of Armenia’s attack on Kalbajar region wounded two of its soldiers.

Tensions between Baku and Yerevan have escalated sharply in recent months, as both sides accuse the other of violating agreements and cross-border gunfire.

“As a result of firing by the Azerbaijani army in the direction of Armenian positions located in the Sotk area, there are two dead and one wounded on the Armenian side,” the ministry said on Friday.

Meanwhile, Azerbaijan said that Armenia had struck positions in the Kalbajar region using drones, wounding two Azerbaijani servicemen. It said it was taking “retaliatory measures”.

Nagorno-Karabakh, internationally recognised as part of Azerbaijan, has been a source of conflict between the two Caucasus neighbours since the years leading up to the collapse of the Soviet Union in 1991.

Yerevan and Baku have fought two wars for control over the region, which is internationally recognised as part of Azerbaijan but largely populated by ethnic Armenians.

The two sides have been unable to reach a lasting peace settlement despite mediation efforts by the European Union, United States and Russia.

Azerbaijan accused Armenia of building up troops along the two countries’ volatile borders in August, while Armenia accused Azerbaijan’s military of opening fire on European Union observers.

Separatist authorities in the breakaway region of Nagorno-Karabakh said in June that four Armenian soldiers were killed by Azerbaijani fire in Nagorno-Karabakh.