Armenia said on Tuesday that four of its soldiers were killed by Azerbaijani fire along the heavily militarized border, the first fatal incident since they began negotiating a deal to end more than 30 years of intermittent war last year.
Fatal exchanges have been common along the closed, roughly 1,000 km (621 mile) frontier since 1988 when Armenia and Azerbaijan first went to war over the breakaway region of Nagorno-Karabakh, but the situation had calmed amid peace talks in recent months.
Tuesday's incident was the biggest since hundreds died when Azerbaijan retook Karabakh in September, prompting an exodus of the region's ethnic Armenian population.
Armenia's Defence Ministry said in a statement that the four soldiers had been killed and another was wounded at a combat post near the southern Armenian village of Nerkin Hand. Azerbaijan's border service said in a statement that it had staged "a revenge operation" for a "provocation" it said Armenian forces had committed the day before.
"The military and political leadership of Armenia is fully responsible for the incident," it said, adding that future provocations would face more serious measures.
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