Armenia-backed fighters have handed over the bodies of five Azerbaijani soldiers, two days after they were killed along the boundary with the breakaway Nagorno-Karabakh region.
The troops died in clashes early on Saturday in the remote Khojavend and Fizuli regions, but the separatists prevented the recovery of the bodies until Monday, Azerbaijan's defence ministry said.
International mediators from the OSCE Minsk Group had called on the two sides "to keep heavy military equipment in its present positions and to allow recovery of the dead".
The rebels said in a statement: "Evacuation of bodies did not take place because Azerbaijan violated agreements."
The breakaway region's self-declared defence ministry accused Azerbaijan's military of trying to infiltrate its territory.
There were no casualties on their side, the separatists said.
Clashes over control of the Nagorno-Karabakh region, which lies inside Azerbaijan but is controlled by ethnic Armenians, have stirred fears of a wider conflict breaking out in the South Caucasus, which is crisscrossed by oil and gas pipelines.
The conflict first erupted in 1991 and a ceasefire was agreed in 1994.
But Azerbaijan and Armenia regularly trade accusations of violence around Nagorno-Karabakh and along the Azerbaijan-Armenia border.
The ceasefire was broken last April when dozens were killed.
Efforts to secure a permanent settlement have failed despite mediation led by France, Russia and the United States.