Azerbaijani President Ilham Aliyev and Armenian President Serzh Sarkisian began a meeting in Vienna on May 16 to discuss a possible settlement over Azerbaijan’s breakaway Nagorno-Karabakh region.

Russian media reports said their face-to-face talks were being mediated by Russian Foreign Minister Sergei Lavrov, U.S. Secretary of State John Kerry, and French Foreign Minister Jean-Marc Ayrault, who co-chairs the Minsk Group of the Organization for Security and Cooperation in Europe (OSCE).

The Vienna meeting is the first face-to-face encounter between Aliyev and Sarkisian since a truce in early April halted four days of fierce fighting in and around Nagorno-Karabakh between Armenia-backed separatists and Azerbaijan’s military.

Earlier on May 16, European Union foreign policy chief Federica Mogherini met with Aliyev and Sarkisian to discuss how to shore up the shakey cease-fire

Kerry and Lavrov also met separately in Vienna on May 16 for talks on the war in Syria, Libya’s crisis, and Nagorno-Karabakh.

Baku and Yerevan have been locked in conflict over Nagorno-Karabakh since the waning years of the Soviet Union.

Populated mainly by ethnic Armenians, the territory declared independence from Azerbaijan in a 1988-94 war that killed an estimated 30,000 people and displaced hundreds of thousands.

"For now, the main aim for the mediators is to just calm down the tensions along the front line," Armenia-based political analyst Hrant Melik-Shahnazaryan told the AFP news agency. "The signing of any documents or reaching of any other sort of agreements is highly unlikely."

"If the meeting in Vienna does not yield any results, then the likelihood of a repeat of April fighting increases," according to Elkhan Shainoglu of the Atlas think tank in the Azerbaijani capital, Baku.

Internationally mediated negotiations with the involvement of the Minsk Group have failed since the early 1990s to resolve the conflict.

On April 2, Nagorno-Karabakh saw its worst violence since a shaky cease-fire was reached in 1994 between Azerbaijan and Armenia-backed separatists.

A fresh Russian-brokered cease-fire deal went into effect on April 5, but the sides in the conflict have been accusing each other of breaching the truce agreement.

About 75 soldiers from both sides were killed in April, along with several civilians.

And there are fears of a possible escalation, with Turkey strongly backing Azerbaijan and Russia, which has sold weapons to both sides, obliged to protect Armenia by a mutual security pact.

A day before meeting in Vienna, the defense ministers of Azerbaijan, Turkey, and Georgia met to discuss joint military exercises.

"To increase the combat capabilities and combat readiness of Azerbaijan, Turkey, and Georgia, we deemed it worthwhile to carry out joint military exercises," Azerbaijani Defense Minister Zakir Gasanov said after the May 15 talks in the Azerbaijani city of Gabala.

"Georgia has expressed a willingness to host several such exercises in 2017," his Georgian counterpart, Tina Khidasheli, said. "We have received consent, so we will prepare for spring 2017."

With reporting by AFP, TASS, and civil.ge

