Azerbaijan and Armenia accused each other of swiftly violating the terms of a ceasefire in Nagorno-Karabakh on Saturday, brokered by Russia.
The ceasefire, clinched after marathon talks in Moscow advocated by President Vladimir Putin, was meant to halt fighting to allow ethnic Armenian forces in Nagorno-Karabakh and Azeri forces to swap prisoners and war dead.
But within minutes of the truce taking effect from midday, both sides accused each other of breaking it.
The Armenian defence ministry accused Azerbaijan of shelling a settlement inside Armenia, while ethnic Armenian forces in Karabakh alleged that Azeri forces had launched a new offensive five minutes after the truce took hold.
Azerbaijan said enemy forces in Karabakh were shelling Azeri territory. Both sides have consistently denied each others' assertions about military activity.
In a statement which suggested the ceasefire was not completely dead however, Azeri President Ilham Aliyev said the warring parties were now engaged in trying to find a political settlement.
The Moscow ceasefire talks were the first diplomatic contact between the two since fighting over the mountainous enclave erupted on Sept. 27, killing hundreds of people. The enclave is internationally-recognised as part of Azerbaijan but is populated and governed by ethnic Armenians.
Russian Foreign Minister Sergei Lavrov, who helped mediate, said in a statement in the early hours of Saturday after more than 10 hours of negotiations that the ceasefire had been agreed on humanitarian grounds.
The International Committee of the Red Cross would help make the truce work, he said.
"The specific terms of the ceasefire still need to be agreed," said Lavrov, who said Armenia and Azerbaijan had also agreed to enter into what he called substantive peace talks.