Azerbaijan's defense ministry said on Wednesday that seven of its soldiers were killed in border clashes with Armenia near the Nagorno-Karabakh region.
"Seven servicemen died and 10 more were wounded in the clashes provoked Tuesday by Armenia," Baku's defense ministry said. Armenia reported one dead, 13 captured, and 24 missing troops.
A Russian-brokered ceasefire was holding Wednesday at the Armenian-Azerbaijani border, officials said, a day after deadly clashes between the arch-foes sparked fears of another flare-up in their territorial dispute.
On Tuesday, clashes between Armenian and Azerbaijani troops left eight soldiers dead in the worst fighting since last year's war over the long-disputed Nagorno-Karabakh region.
The six-week conflict, which claimed the lives of more than 6,500 people, ended last November in a Russia-mediated deal that saw Armenia cede swathes of territory it had controlled for decades.
Tuesday's fighting ended in the evening after mediation by Russia's Defense Minister Sergei Shoigu.
Armenia's Prime Minister Nikol Pashinyan on Tuesday accused Azerbaijan of "targeting Armenia's statehood, sovereignty and independence."
Baku said Yerevan was responsible for a "large-scale military provocation."
Armenia appealed to its Russian ally for military support under the Collective Security Treaty Organisation pact, which obliges Moscow to protect it in the event of a foreign invasion.
"Given that there was an attack on Armenia's sovereign territory, we appeal to the Russian Federation to protect Armenia's territorial integrity," Security Council Secretary Armen Grigoryan said Tuesday.
The same day, Russian President Vladimir Putin discussed the situation with Pashinyan by phone, the Kremlin said in a statement, and agreed to "continue contacts" on the matter.
Before the ceasefire was announced, the European Union and the United Nations called on both sides to cease hostilities.
European Council President Charles Michel on Twitter called for a "full ceasefire," while the U.N. urged Baku and Yerevan to "exercise restraint."
The French foreign ministry in a statement expressed its "deep concern" and called on all parties to respect the agreements that were reached in November 2020.
Since last year's war, both Armenia and Azerbaijan have reported occasional exchanges of fire.
Armenia and Azerbaijan have been locked in a decadeslong dispute over the region of Nagorno-Karabakh, a region that lies within Azerbaijan but was occupied by ethnic Armenian forces backed by Russia since a war there ended in 1994.
Tensions on the two nations' border have been building since May when Armenia protested what it described as an incursion by Azerbaijani troops into its territory. Azerbaijan has insisted that its soldiers were deployed to what it considers its territory in areas where the border has yet to be demarcated. Clashes have been reported ever since.