Armenian troops have killed a second Azerbaijani soldier this week, Baku said Friday, threatening a "severe" response to the latest violence in a long-standing conflict over the disputed Nagorny Karabakh region.
"On March 13, the Armenian armed forces violated the ceasefire. An Azerbaijani soldier was shot dead" in the latest border clash between the arch-foes, Azerbaijan's defence ministry said in a statement.
"Azerbaijan's counter-strike will be severe," it added.
The incident comes after another soldier was killed in an attack on Azerbaijani positions on Wednesday.
Baku and Yerevan have been locked in a dispute over Azerbaijan's Nagorny Karabakh region since a bloody war in the early 1990s.
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.
Despite years of negotiations, the two sides have not signed a final peace deal, with Armenian-populated Karabakh still internationally recognised as part of Azerbaijan.
Karabakh's ethnic-Azeri community -- which before the war made up around 25 percent of the population -- was entirely driven out.
Threatening a shaky 1994 truce, clashes between Azerbaijani and Armenian forces intensified again in January following an unprecedented spiral of violence last year.
At least 18 people from both sides were reported killed and as many wounded this year in sporadic flare-ups on the Armenian-Azerbaijani border, and along the Karabakh frontline.
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.