The de facto military authorities in Azerbaijan's breakaway Nagorno-Karabakh region said three of its fighters were killed and one was seriously wounded in a land-mine explosion on November 21 near the line of contact separating the combatant sides.
The November 22 statement said the servicemen triggered an antitank mine while carrying out engineering work.
Armenian Defense Ministry spokesman Artsrun Hovannisian said the case was not a result of "direct enemy impact."
The deadly incident came shortly after a regional tour by Russian Foreign Minister Sergei Lavrov, who visited Baku and Yerevan on November 19-21 for talks that partially focused on the Nagorno-Karabakh issue.
The Nagorno-Karabakh region, populated mainly by ethnic Armenians, declared independence from Azerbaijan amid a 1988-94 war that claimed an estimated 30,000 lives and displaced hundreds of thousands of people.