The Defense Ministry of Azerbaijan says it has destroyed an Armenian air defense missile system in the breakaway region of Nagorno-Karabakh.

Nagorno-Karabakh is officially part of Azerbaijan, but Armenia-backed separatists seized control of the mainly ethnic-Armenian populated region during the early 1990s in a war that killed some 30,000 people.

Diplomatic efforts to resolve the conflict during the last 25 years have brought little progress.

According to the AP news agency, Azerbaijan's Defense Ministry said its forces on May 15 "destroyed an Osa air defense system along with its crew." The ministry added that the system's 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 denied that there had been casualties.

It warned in a statement that the Azerbaijani "provocation won't be left unanswered."

With additional reporting by AP