Nagorno-Karabakh is in Azerbaijan but has been under the occupation of local ethnic Armenian forces and Armenian soldiers since 1994 when a cease-fire ended six years of fighting.

Attempts to negotiate a peaceful settlement have stalled, and the sides engage in frequent shootings along the buffer zone.

Tuesday's statement from the Nagorno-Karabakh military said the soldier died while repelling an incursion by Azerbaijani forces. It said Azerbaijani troops made eight attempts to cross the buffer zone on Monday and Tuesday, but were pushed back.

Azerbaijan's Defense Ministry rejected the claim in a statement carried by the Interfax news agency.