Armenian and Azerbaijani troops exchanged artillery fire Thursday along their tense border, leaving at least one soldier dead and several others wounded in the latest bout of escalation between the longtime adversaries that threatened to derail their latest attempts at peace talks.

The two countries’ authorities traded blame for triggering the clashes and accused each other of trying to undermine negotiations on a prospective peace deal.

The Armenian Defense Ministry said that Azerbaijani forces opened artillery fire on Armenian positions near the town of Sotk in the eastern Gegharkunik province, leaving four Armenian soldiers wounded.

Azerbaijan’s Defense Ministry said that one Azerbaijani soldier was killed and another one was wounded by Armenian fire.

The exchange of fire follows US-hosted peace talks earlier this month between the Armenian and Azerbaijani foreign minister, which US Secretary of State Antony Blinken said had achieved “tangible progress.” Blinken said that he believed a peace deal could be “within sight, within reach” and praised the two sides for coming together to try to find common ground.

US engagement in the conflict challenged Russia’s influence in the area it regards as part of its historic sphere of influence at the time when Moscow is busy with the fighting in Ukraine.

The European Union also sought to step up mediation efforts, planning to host Sunday’s meeting in Brussels between Armenian Prime Minister Nikol Pashinyan and Azerbaijani President Ilham Aliyev.

But on Thursday, Armenia and Azerbaijan quickly accused each other of initiating the hostilities to block the prospective peace talks.

The Armenian Foreign Ministry charged that Azerbaijan was trying to “derail the process of negotiations through the use of force and exert pressure on Armenia.”

Azerbaijan, in turn, accused Armenia of a “deliberate provocation” reflecting the lack of interest in the peace process. “All responsibility for the deliberate aggravation of the situation lies with the military-political leadership of Armenia,” the Azerbaijani Foreign Ministry said in a statement.

Despite Thursday’s clashes, Pashinyan confirmed his intention to travel to Brussels on Sunday for talks with Aliyev, but said that chances for reaching a quick deal are small. Azerbaijan also confirmed that Aliyev was set to attend the meeting.

Armenia and Azerbaijan have been locked in a decades-old conflict over Nagorno-Karabakh, which lies within Azerbaijan but in 1994 came under the control of ethnic Armenian forces backed by Armenia, which also seized sizable surrounding Azerbaijani areas.

In six weeks of fighting in 2020, Azerbaijan reclaimed control of a large part of Nagorno-Karabakh and all the surrounding territory previously occupied by Armenians. The hostilities ended with a Moscow-brokered truce that saw the deployment of a Russian peacekeeping force of about 2,000 troops.

In an apparent effort to retain its position as a key power broker in the region, Russia also has recently tried to prepare the talks between the Armenian and Azerbaijani leaders.