BAKU/YEREVAN (Reuters) - Five Azeri soldiers were killed in clashes with Armenia-backed separatists along the boundary with the breakaway Nagorno-Karabakh region, Azerbaijan’s defense ministry said on Monday, with each side accusing the other of an attempted incursion.

Clashes over control of Nagorno-Karabakh, which lies inside Azerbaijan but is controlled by ethnic Armenians, have stoked fears of a wider conflict breaking out in the South Caucasus, which is crisscrossed by oil and gas pipelines.

The Azeri defense ministry said the clashes had occurred early on Saturday in the remote Khojavend and Fizuli regions. It said the separatists had handed over the bodies of the five dead soldiers on Monday.

Nagorno-Karabakh’s self-declared defense ministry said its side had suffered no casualties in the clashes.

International mediators urged the two sides “to keep heavy military equipment in its present positions and to allow recovery of the dead”.

Fighting between ethnic Azeris and Armenians first erupted in 1991 and a ceasefire was agreed in 1994. But Azerbaijan and Armenia have regularly traded accusations of violence around Nagorno-Karabakh and along the Azeri-Armenian border.

The ceasefire was broken last April when dozens were killed. Efforts to secure a permanent settlement of the Nagorno-Karabakh conflict have failed despite mediation led by France, Russia and the United States.