An Azerbaijani soldier and an Armenian were killed on Friday on the second day of border clashes between the two sides' forces that took place two days before high-level talks on a long-term peace deal.
Mortars and drones were used in the latest clashes, which come ahead of Sunday's EU-sponsored meeting in Brussels between Armenian Prime Minister Nikol Pashinyan and Azerbaijani President Ilham Aliyev.
In the latest skirmishes, Armenia's Defense Ministry said its forces had been fired mortars and small arms near the village of Sotak, near the border. The ministry added that drones had also been deployed.
"Following hostile fire, one person was killed during the fighting on the Armenian side and two others were wounded," the ministry said, adding that the exchange of fire eventually stopped.
Azerbaijan's defence ministry said it had stopped a drone attack by Armenia on its positions in the Kalbajar region on its side of the border.
It later stated that one of its soldiers had been killed and that Azerbaijani forces were in control of the situation.
Tensions have escalated as efforts have intensified to get the two rivals to reach a peace deal despite disagreements over border demarcation and other issues.
The two countries have disputed control of Nagorno-Karabakh, a region recognized as part of Azerbaijan but inhabited mainly by Armenians, and has repeatedly erupted into fighting.
The foreign ministers of the two sides met in early May in the United States, which hosted four days of intensive talks between delegations from the two countries.
The two sides said on Thursday they were acting in self-defense and blamed each other for the shooting first.
Pashinyan accused Azerbaijan of seeking to "undermine the talks" scheduled in Brussels, stressing that there was a "very slim" chance of reaching a peace deal with Aliyev during the meeting.
The draft agreement "is still at a preliminary stage, and it is too early to talk about the possibility of signing it", he said.
Azerbaijan last month set up a checkpoint at the entrance to the Lachin corridor, the only road linking Armenia to Nagorno-Karabakh, in a move Yerevan said was a "flagrant violation" of the 2020 ceasefire.
It is noteworthy that Baku and Yerevan signed a Moscow-mediated ceasefire in the fall of 2020 after Baku seized territory in the Karabakh region, and Russian soldiers are deployed to supervise compliance with the ceasefire in that area, but Armenia has complained for months about their ineffectiveness.