Armenia and Azerbaijan on Thursday blamed each other for gunfire along their restive border, days ahead of EU-hosted talks aimed at resolving their three-decade territorial dispute.
The leaders of the two countries are due to hold talks in Brussels on Saturday as part of a push to normalise relations between the two neighbours in the Caucasus.
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 aimed at ending the dispute over the enclave of Nagorno-Karabakh.
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 defence ministry said in a statement, adding that three of its soldiers had been wounded.
Azerbaijan's defence ministry said that "the Armenian side has once again violated the ceasefire agreement" with "large-calibre weapons" that wounded one Azerbaijani soldier and the mortar fire was continuing.
The incident comes just days before European council President Charles Michel is to host Armenia's Nikol Pashinyan and Azerbaijan's Ilham Aliyev for talks in Brussels.
The two leaders had also agreed to meet together with the leaders of France and Germany on the sidelines of a European summit in Moldova on June 1, according to the EU.
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 Nagorno-Karabakh, a majority-Armenian region inside Azerbaijan.
Tens of thousands of people have been killed in two wars over the region, one lasting six years and ending in 1994, and the second in 2020, which ended in a Russia-negotiated ceasefire deal.
But clashes have broken out regularly since then.
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.