Nagorno-Karabakh is officially part of Azerbaijan, but since a separatist war ended in 1994 it has been under the control of forces that claim to be local ethnic Armenians but that Azerbaijan claims include regular Armenian military. Efforts to negotiate a settlement have failed, and frequent clashes have continued.
Azerbaijan's Defense Ministry said its forces today destroyed an Osa air defense system along with its crew, adding that its deployment near the line of control was a "provocation" and a threat to Azerbaijani aircraft.
The Nagorno-Karabakh separatist authorities confirmed that an Azerbaijani attack damaged its equipment, but said there were no casualties. It warned in a statement that the Azerbaijani "provocation won't be left unanswered.