Nagorno-Karabakh says its forces have killed two Azerbaijani soldiers in an operation to recover the bodies of three helicopter crew members whose craft was shot down by Azerbaijan this month.

The separatist region's army revealed the overnight operation in a statement Saturday.

The Azerbaijani region and some adjacent territory have been under the control of Armenian soldiers and ethnic Armenian local troops since the end of a six-year separatist war in 1994. Both sides report frequent shootings and attempted incursions along the cease-fire line, but a recent outbreak of fighting has been the worst in many years.

The Azerbaijani defense ministry denied there had any rescue operation, Azerbaijani media reported.

The helicopter was shot down on Nov. 11 and fell inside the demilitarized zone separating the two sides.