Russia had announced on Tuesday that it had negotiated a ceasefire following clashes that killed at least 100 troops on both sides.
But Baku and Yerevan have now both accused the other of violating the truce.
On Wednesday, Armenia’s defense ministry said “the enemy re-launched its attack by using artillery, mortar, large-calibre firearms in the directions of Jermuk, Verin Shorzha” on the border.
“Despite a clear reaction from the international community over the situation, in fact Azerbaijan’s military-political leadership continues its acts of aggression against the sovereign territory of Armenia, targeting both military and civilian infrastructure.”
Tuesday’s escalation came as Yerevan’s closest ally Moscow — which deployed thousands of peacekeepers in the region after the 2020 war — is distracted by its six-month-old invasion of Ukraine.
Armenia appealed to world leaders for help and the European Union, United States, France, Russia, Iran and Turkey all expressed concern over the escalation and called for an end to fighting.
The neighbors fought two wars — in the 1990s and in 2020 — over the disputed Nagorno-Karabakh region, Azerbaijan’s Armenian-populated enclave.
The six weeks of fighting in autumn 2020 claimed the lives of more than 6,500 troops from both sides and ended with a Russian-brokered ceasefire.
Under the deal, Armenia ceded swathes of territory it had controlled for decades and Moscow deployed about 2,000 Russian peacekeepers to oversee the fragile truce.
During EU-mediated talks in Brussels in May and April, Aliyev and Pashinyan agreed to “advance discussions” on a future peace treaty.
Ethnic Armenian separatists in Nagorno-Karabakh broke away from Azerbaijan when the Soviet Union collapsed in 1991. The ensuing conflict claimed around 30,000 lives.