Yerevan (AFP) - Azerbaijani troops on Friday killed an Armenian soldier in the latest border clash between the arch-foes who are locked in a longstanding conflict over the disputed Nagorny Karabakh region, Armenia said.

"Today (Friday), Azerbaijani armed forces violated the ceasefire," at the Caucasus neighbours' shared border, Armenian Defence Ministry spokesman, Artsrun Hovannisyan, told AFP.

"An Armenian serviceman has been killed in action," he said, claiming that the Azerbaijani side -- which he accused of "military provocations" had suffered "substantial losses".

Azerbaijani officials were not available for immediate comment.

Armenia and Azerbaijan have been at loggerheads over the Nagorny Karabakh region since a bloody war in the early 1990s following the breakup of the Soviet Union.

Yerevan-backed ethnic Armenian separatists seized control of Karabakh and several other regions of Azerbaijan during the conflict that left some 30,000 dead.

Despite years of negotiations, the two countries have not signed a final peace deal to cement a 1994 ceasefire.

The predominantly Armenian-populated region is internationally recognised as part of Azerbaijan.

Azerbaijan, whose military spending exceeds Armenia's entire state budget, has threatened to take back the disputed territory by force if negotiations fail to yield results.

Armenia, which is backed militarily by Russia, says it could crush any offensive.

Clashes between Azerbaijani and Armenian forces across their shared border and along the Karabakh frontline have intensified in the past year.