On Sunday, Armenia and Azerbaijan accused each other of violating a new humanitarian ceasefire in the fight over the Nagorno-Karabakh mountain enclave, hours after it was agreed, reports Reuters.

After a week-old Russian-brokered ceasefire failed to stop the worst fighting in the South Caucasus since the 1990s, the truce agreed on Saturday came into force at midnight (2000 GMT). Since fighting began on Sept. 27, at least 750 people have been killed.

The Aghdam region, adjacent to Nagorno-Karabakh, was under Armenian shelling at 1010 GMT, the Azeri defense ministry said. It said that Armenian military units opened fire overnight along the border with large-caliber weapons, which Armenia denied.

Armenia claimed that twice during the night, the Azeri army had fired and used artillery and accused Baku of rejecting his request to remove the wounded soldiers from the battlefield.

The foreign ministry said in a statement, "This step ... was categorically rejected by Baku." The statement was called Misinformation by Baku.

"The enemy fired at the vicinity of the city of Jabrail, as well as the villages of this region ... using mortars and artillery," the Azeri defense ministry said. The Azeri army "took adequate retaliatory measures" was added.

The ministry said that Armenian Su-25 warplanes were shot down by Azeri military units, "which were trying to inflict airstrikes on the positions of the Azeri army in the Jabrail region." Yerevan quickly denied that.

Nagorno-Karabakh officials said Azeri forces had launched an attack on the military positions of the enclave and there were casualties and wounded on both sides.

Nagorno-Karabakh is a mountain region recognized internationally as part of Azerbaijan, but populated by ethnic Armenians and governed by them.

The aim of the ceasefire earlier this month was to let the sides swap detainees and bodies of those killed in the clashes, but it had little impact on the enclave's fighting.

On Saturday, the new truce was announced after Russian Foreign Minister Sergei Lavrov spoke by telephone with his Armenian and Azeri counterparts and called on the parties to observe the truce that he mediated a week ago.

Russia, France, and the United States are members of the Minsk Group, which, under the umbrella of the Organisation for Security and Cooperation in Europe (OSCE), has tried to help resolve the conflict.

On Saturday, Baku said 60 Azeri civilians had been killed and 270 wounded since the fighting began on 27 September. It did not reveal its military casualties.

Nagorno-Karabakh says 673 of its military personnel and 36 civilians have been killed.