The soldier was killed at the north-eastern sector of the state border, Armenian defence ministry spokesman Artsrun Hovannisyan told AFP.

The death is the latest in several months of violence along the line dividing the warring sides and takes the number of people reported killed on both sides this year to 24.

Yerevan-backed ethnic Armenian separatists seized control of Karabakh and another seven adjacent districts of Azerbaijan during the conflict that left some 30,000 dead.

Undermining a shaky 1994 truce, clashes between Azerbaijani and Armenian forces across the arch-foes' border and along the Karabakh frontline intensified last year.

Despite years of negotiations, the two sides have not signed a final peace deal, and Armenian-populated Karabakh is still internationally recognised as part of Azerbaijan.

However, Karabakh's ethnic-Azeri community -- around a quarter of the population before the war -- was entirely driven out.

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

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