YEREVAN, Armenia — Russia's top diplomat said Tuesday that about 2,000 fighters from the Middle East have joined the fighting over Nagorno-Karabakh, the worst outbreak of hostilities in the conflict between Armenia and Azerbaijan in more than a quarter-century.
Russian Foreign Minister Sergey Lavrov's statement came as the warring parties traded accusations over new attacks in the region.
"We are certainly worried about the internationalization of the Nagorno-Karabakh conflict and the involvement of militants from the Middle East," Lavrov said in an interview with the Russian business daily Kommersant. "We have repeatedly asked foreign players to use their potential to stop the transfer of militants, whose number in the conflict zone is approaching 2,000."
Lavrov added that Russian President Vladimir Putin raised the issue in last week's phone call with Turkish President Recep Tayyip Erdogan.
Nagorno-Karabakh lies within Azerbaijan but has been under the control of ethnic Armenian forces backed by Armenia since a war there ended in 1994. The latest outburst of hostilities began Sept. 27 and has left hundreds — perhaps thousands — dead, marking the worst escalation of fighting since the war's end.
Azerbaijan has relied on strong support from its ally Turkey, which has trained Azerbaijani military and provided it with strike drones and long-range rocket systems. Armenian officials accuse Turkey of being directly involved in the conflict and sending mercenaries from Syria to fight on Azerbaijan's side.
Turkey has denied deploying combatants to the region, but a Syrian war monitor and Syria-based opposition activists have confirmed that Turkey has sent hundreds of Syrian opposition fighters to fight in Nagorno-Karabakh.
The heavy fighting involving heavy artillery, rockets and drones has raged despite repeated international attempts to end hostilities. A U.S.-brokered truce frayed immediately after it took effect last week, just like two previous cease-fires negotiated by Russia, and the latest pledge by Armenia and Azerbaijan not to target residential areas was broken hours after it was made Friday. The warring sides have repeatedly blamed each other for violations.
Artillery fire hit the region's capital Stepanakert on Tuesday night and Nagorno-Karabakh emergencies ministry also said three rockets hit the strategically key city of Shushi.
Azerbaijani President Ilham Aliyev has insisted that Azerbaijan has the right to reclaim its territory by force after three decades of fruitless international mediation. He said that Armenia must pledge to withdraw from Nagorno-Karabakh as a condition for a lasting truce.
Azerbaijani troops have reclaimed control of several regions on the fringes of Nagorno-Karabakh and pressed their offensive into the separatist territory from the south, trying to cut a link between the separatist territory and Armenia.
Lavrov said that Russia was continuing to push for hostilities to end, noting that it's working on a set of verification measures needed to achieve a lasting cease-fire, including the possible deployment of international observers under the aegis of the Organization for Security and Cooperation in Europe.