Nagorno-Karabakh says its forces have killed two Azerbaijani soldiers in an operation to recover the bodies of three crew members whose helicopter was shot down by Azerbaijan earlier this month.
The separatist region's military revealed the overnight operation in a statement on November 22. It said Karabakh forces did not suffer any losses.
Azerbaijan's defense ministry denied there had been any rescue operation, Azerbaijani media reported.
The helicopter was shot down on November 11 and fell inside the demilitarized zone separating the two sides.
Armenia and Azerbaijan have been locked in a conflict over Azerbaijan's breakaway region of Nagorno-Karabakh for years.
Armenian-backed separatists seized the mainly Armenian-populated region from Azerbaijan during a war in the early 1990s that killed some 30,000 people.
Both sides report frequent shootings and attempted incursions along the cease-fire line, but a recent outbreak of fighting has been the worst in recent years.
With additional reporting by AP and Interfax