Fighting between Armenian and Azerbaijani forces escalated Tuesday, with Azerbaijan reporting seven more troops killed, including a general, and Armenia saying it has lost two servicemen.

Skirmishes on the volatile border between the two South Caucasus nations began Sunday. The new losses bring the number of Azerbaijani troops killed to 11. Armenia previously reported five of its troops wounded.

An Azerbaijani civilian also died from Armenian shelling Tuesday, Azerbaijan’s Foreign Ministry said, bringing total casualties from the fighting to 14.

In this grab taken from the Associated Press Television footage made available on Monday, April 4, 2016, Armenian soldiers pass a Grad missile launcher on Sunday, April 3, 2016, in the village of Mardakert, in the separatist region forces of Nagorno-Karabakh. Skirmishes on the volatile Armenia-Azerbaijan border escalated Tuesday, July 14, 2020 marking the most serious outbreak of hostilities between the neighbors since the fighting in 2016. (AP Photo, File)

In this grab taken from the Associated Press Television footage made available on Monday, April 4, 2016, Armenian soldiers pass a Grad missile launcher on Sunday, April 3, 2016, in the village of Mardakert, in the separatist region forces of Nagorno-Karabakh. Skirmishes on the volatile Armenia-Azerbaijan border escalated Tuesday, July 14, 2020 marking the most serious outbreak of hostilities between the neighbors since the fighting in 2016. (AP Photo, File)

The two neighbors in the South Caucasus have been locked in conflict over Nagorno-Karabakh, a region of Azerbaijan that has been under the control of ethnic Armenian forces backed by Armenia since a war there ended in 1994. International efforts to settle the conflict have stalled.

Armenian and Azerbaijani forces have frequently engaged in clashes. The current skirmishes appear to mark the most serious spike in hostilities since 2016 when scores were killed in four days of fighting.

The latest incident began Sunday when Armenian and Azerbaijani troops exchanged fire in the northern section of their border. Officials in both countries blamed each other for starting the fighting and said that sporadic shelling has continued.

Azerbaijan's Defense Ministry said two senior officers, Maj. Gen. Polad Hashimov and Col. Ilgar Mirzayev, were killed in fighting Tuesday along with five other servicemen.

Armenian officials claimed that Azerbaijani drones launched an attack on the Tuvush province town of Berd, targeting civilian infrastructure. Defense Ministry spokeswoman Shushan Stepanyan said that one of Azerbaijani drones was downed.

The Azerbaijani military denied losing a drone and in turn claimed that its forces shot down an Armenian drone and destroyed an Armenian cannon along with its crew.

As hostilities continued, Armenia also accused Azerbaijan of launching cyberattacks on Armenian government websites.

Armenian Prime Minister Nikol Pashinyan on Monday accused Azerbaijan of provoking the clashes and warned that it would “bear responsibility for the unpredictable consequences.” Azerbaijani President Ilhan Aliyev denounced what he described as “another provocation of Armenia” and vowed to protect Azerbaijan’s national territory.

Turkey, which has close ethnic and cultural ties with Azerbaijan, has voiced strong support to Baku in the conflict.

The United States and Russia, which co-chair the Minsk group of the Organization for Security and Cooperation in Europe that has tried to negotiate a settlement of the Nagorno-Karabakh conflict, have condemned the violence and called for restraint.

Russian Foreign Minister Sergey Lavrov had separate calls with his counterparts in Armenia and Azerbaijan on Monday to call for an immediate ceasefire.

Russian President Vladimir Putin's spokesman, Dmitry Peskov, said Tuesday that Moscow was “deeply worried” about the fighting and stands ready to play mediator.

Vladimir Isachenkov in Moscow contributed to this report.