Troops from Azerbaijan and Armenia exchanged fire with weapons including mortars and drones on their joint border on Friday, killing one soldier from each side two days before top-level talks on a long-term peace deal.
It was the second straight day of exchanges of fire - ahead of Sunday's planned meeting in Brussels between Armenian Prime Minister Nikol Pashinyan and Azeri President Ilham Aliyev.
One Azeri soldier died in Thursday's hostilities.
The two ex-Soviet states have fought two wars in 30 years focusing on the disputed region of Nagorno-Karabakh, recognised as part of Azerbaijan but populated mainly by ethnic Armenians.
In a six-month conflict in 2020, Azerbaijan recovered swathes of territory lost in an earlier war that gripped the region amid the collapse of Soviet rule.
In the latest skirmish, Armenia's Defence Ministry said its forces came under fire with mortars and small arms near the village of Sotk, close to the border. The ministry said drones were also deployed.
"In the wake of enemy fire, the Armenian side has one killed in action and one wounded," the ministry said, adding the exchanges eventually died down.
Azerbaijan's Defence Ministry said it had cut short a drone attack by Armenia on its positions in the Kalbajar district on its side of the border. It later reported that one of its servicemen had been killed and that Azeri troops controlled the situation.
Tensions have risen while efforts intensify to get the two rivals to reach a peace deal despite differences on border demarcation and other issues. Talks have generally been staged under the jurisdiction of the European Union or Russia - which brokered the truce that ended the fighting in 2020.
Foreign ministers from both sides met last week in the United States.
Azerbaijan last month installed a checkpoint at the entry to the Lachin Corridor - the only road linking Armenia to Karabakh - in a move that Yerevan said was a "gross violation" of the 2020 ceasefire.
On Thursday, both sides said they were acting in self-defence and blamed the other for firing first.
Armenia said four of its servicemen had been injured. Pashinyan said that incident was an attempt by Azerbaijan to disrupt peace talks.
The latest clashes are also seen as a test of Russia's ability to influence events in the South Caucasus.
Russia is a formal ally of Armenia through a mutual self-defence treaty, but also strives for good relations with Baku. Moscow says the 2020 peace accord it brokered is the only basis for a long-term solution.
(Reporting by Ron Popeski; Editing by Frank Jack Daniel and Rosalba O'Brien)
