Skirmishes have continued around Nagorno-Karabakh with Azerbaijan and Armenia blaming each other for cease-fire violations.

Azerbaijan's Defense Ministry said Friday its troops returned fire after Armenian forces shelled Azerbaijani military positions and populated areas. The Armenian side accused Azerbaijan of shelling its positions, killing two Armenian soldiers overnight.

The gunbattles threaten to derail the Russia-brokered truce declared at midday Tuesday following several days of intense battles which marked the worst violence since a separatist war ended in 1994. The war left Nagorno-Karabakh, officially a part of Azerbaijan, under the control of local ethnic Armenian forces and the Armenian military. Armenian forces also occupy several areas outside the Karabakh region.

Azerbaijan has said 31 of its soldiers have been killed since Saturday; Armenia's Defense Ministry has acknowledged the loss of 44.