Azerbaijan on Thursday said one of its soldiers was killed in a clash with archrival Armenia along their restive border, days ahead of EU-hosted talks aimed at resolving the three-decade territorial dispute.
"A soldier from the Azerbaijani army was killed after a provocation from the Armenian forces," Azerbaijan's Defense Ministry said. In contrast, Armenia said four soldiers were wounded in the clashes.
The leaders of the two South Caucasus neighbors are due to hold talks in Brussels on Saturday as part of a push to normalize relations between their countries.
The European Union-hosted meeting comes after the United States said "tangible progress" had been made at talks between foreign ministers in Washington last week to end the dispute over the Karabakh region.
But on Thursday, both sides accused each other of shooting along their border.
"Azerbaijani forces are shooting artillery and mortars at Armenian position in the Sotk region" in the east, Armenia's Defense Ministry said.
Azerbaijan's Defense Ministry said that "the Armenian side has once again violated the cease-fire agreement" with "large-caliber weapons" and that the mortar fire was continuing.
The incident comes just days before European Council President Charles Michel is to host Armenian Prime Minister Nikol Pashinian and Azerbaijani President Ilham Aliyev for talks in Brussels.
According to the EU, the two leaders had also agreed to meet with the leaders of France and Germany on the sidelines of a European summit in Moldova on June 1.
Majority-Christian Armenia and Azerbaijan, whose population is mostly Muslim, were both republics of the Soviet Union that gained independence in 1991 when the USSR broke up.
They have gone to war twice over disputed territories, mainly Karabakh, a region internationally recognized as part of Azerbaijan but occupied by Armenia for nearly three decades.
Tens of thousands of people were killed in the two wars over the region, one lasting six years and ending in 1994 and the second in 2020, which ended in a Russia-negotiated cease-fire deal that saw Moscow deploy a peacekeeping contingent along the Lachin corridor, the only road linking Armenia to the enclave.
However, a dispute over establishing a checkpoint on the Lachin corridor last month has brewed violent tension between the rival nations, which saw another half a dozen people killed from both sides since last December.
Baku said the border checkpoint was created in response to security threats from Armenia, citing the transfer of weapons and ammunition to the Karabakh region. Yerevan denied the charges and claimed the move violated the cease-fire.
Armenia, which relies on Russia as a security guarantor, is also frustrated over what it sees as the Kremlin's failure to fulfill its peacekeeping role in the territory.
Washington said previously that it was "deeply concerned" by the checkpoint.
The Western mediation efforts to resolve the conflict come as major regional power Russia has struggled to maintain its decisive influence due to the fallout from its war on Ukraine.