Four soldiers from Azerbaijan have been killed in clashes in the disputed Nagorno-Karabakh region, Azerbaijan's defence ministry says.
The reports come only weeks after a six-week war over the territory which ended when Azerbaijan and Armenia signed a ceasefire.
Armenia meanwhile said six of its own troops were wounded in what it called an Azerbaijani military offensive.
Nagorno-Karabakh has long been a trigger for violence between the two.
The region is recognised as part of Azerbaijan but has been run by ethnic Armenians since 1994 after the two countries fought a war over the territory which left thousands dead.
A Russian-brokered truce failed to bring about lasting peace and the area, claimed by both sides, has been prone to intermittent clashes.
What does the peace deal say?
- Signed on 9 November, it locked in the territorial gains Azerbaijan made during the war, including the region's second-largest city Shusha
- Armenia promised to withdraw troops from three areas
- 2,000 Russian peacekeepers deployed to the region
- Azerbaijan also gained a overland route to Turkey, its ally, by gaining access to a road link to an Azeri conflict on the Iran-Turkey border called Nakhchivan
- The BBC's Orla Guerin said that, overall, the deal was regarded as a victory for Azerbaijan and a defeat for Armenia.
The latest conflict began at the end of September, killing around 5,000 soldiers on both sides.
At least 143 civilians died and thousands were displaced when their homes were damaged or soldiers entered their communities.
- Why did Armenia and Azerbaijan go to war?
- Russian influence under threat in its own backyard
Both countries have accused the other of violating the terms of the November peace deal and the latest hostilities flout the ceasefire.
The agreement was described by Armenian Prime Minister Nikol Pashinyan as "incredibly painful both for me and both for our people".