MOSCOW, November 9. /TASS/. The Collective Security Treaty Organization (CSTO) is deeply concerned over the incident with the Russian Mi-24 helicopter, which was downed in Armenia on Monday. The incident was brought upon by the recent escalation of tensions in Nagorno-Karabakh, CSTO Spokesman Vladimir Zainetdinov told reporters on Monday.

"We deeply regret the fact that the escalation of the Karabakh conflict led to such tragic consequences. We express our deep concern over the incident, and we send our condolences to the families and loved ones of the crewmembers that were killed," he said. "We will wait for the investigation to conclude to determine where the shot was coming from."

Earlier on Monday, the Russian Defense Ministry informed that a Russian Mi-24 helicopter had been downed over Armenia near the border with Azerbaijan from a man-portable air-defense system. Two crewmembers were killed, one was injured. Azerbaijan later claimed responsibility for the crash, informing that it downed the Russian helicopter by mistake and offering to pay damages.

Renewed clashes between Azerbaijan and Armenia erupted on September 27, with intense battles raging in the disputed region of Nagorno-Karabakh. The area experienced flare-ups of violence in the summer of 2014, in April 2016 and this past July. Azerbaijan and Armenia have imposed martial law and launched mobilization efforts. Both parties to the conflict have reported casualties, among them civilians. Hostilities in the region continue despite the previously reached ceasefire agreements.