Azerbaijani officials announced five Armenian and one Azerbaijani soldiers were killed in overnight clashes on Saturday.
Azerbaijani Defence Ministry said that Armenian soldiers launched more than 100 attacks on various parts of the frontline firing in northwestern Gazakh region of Azerbaijan from their posts in northeastern Noyemberyan region of Armenia.
At least five Armenian soldiers were killed when Azerbaijani soldiers fired back as a response, the Azerbaijani sources said.
Armenian Defense Ministry and officials in the self proclaimed Nagorno-Karabakh disputed what Baku said and accused Azerbaijani army of violating the cease-fire regime in the conflict zone.
"Shots were fired throughout the night. The enemy suffered casualties and damage. The Armenian side did not," Armenian Defense Ministry spokesman Artsrun Hovhanisyan wrote on Facebook, claiming that no Armenian troops were killed in the clashes.
Sporadic exchanges of fire continue between Azerbaijani and Armenian forces on the border since 1994, when the two countries signed a cease-fire agreement to end the war over Nagorno-Karabakh region following the Armenian invasion.
Baku demands Yerevan the return of a quarter of its territory which is illegally occupied and recognised as being part of post-Soviet independent Azerbaijan according to international law.
The de facto independent Nagorno-Karabakh declared itself a republic via a plebiscite in 1992 to which only local Armenian population attended, but it was never recognised as a state by the United Nations member states, even by Armenia itself.
Azeri ethnic population in the region is ethnically cleansed and is inhabited by Armenians now.
Before the fall of Soviet Union, the area was part of Azerbaijani Socialist Republic.
Clashes occur between the two sides at regular intervals since a cease-fire was signed in 1994.