Azerbaijan's defence ministry announced a unilateral ceasefire Sunday against the separatist region of Nagorno-Karabakh, but rebel forces in the area said that they continued to come under fire from Azerbaijani forces.

Fighting in what was a dormant conflict for two decades flared up over the weekend with a boy and at least 30 troops killed on both sides. Each side blamed the other for Saturday's escalation, the worst since the end of a full-scale war in 1994.

The defence ministry said, in response to pleas from international organizations, it will be unilaterally "suspending a counter-offensive and response on the territories occupied by Armenia." The ministry added it will not focus on fortifying the territory that Azerbaijan has "liberated." It did not elaborate.

Simmering religious tensions

Nagorno-Karabakh, a region in Azerbaijan, has been under the control of local ethnic Armenian forces and the Armenian military since a war ended in 1994 with no resolution of the region's status. The conflict is fuelled by long-simmering tensions between Christian Armenians and mostly Muslim Azeris.

Armenian forces also occupy several areas outside Nagorno-Karabakh proper. The sides are separated by a demilitarized buffer zone, but small clashes have broken out frequently.

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Doctors render aid to 12-year-old Gevorg Grigoryan, who was wounded in a missile barrage by Azerbaijani forces, in a hospital in Stepanakert, in the separatist Nagorno-Karabakh region on Saturday. At least one child was killed what one official called the worst clashes since 1994. ( (Areg Balayan/PAN Photo via Associated Press)

Earlier Sunday, a spokesman for Azerbaijan's defence ministry, Vagif Dargyakhly, said Azerbaijani positions came under fire overnight and that civilian areas also were hit.

On Saturday, Armenia said 18 soldiers were killed and Azerbaijan reported 12 dead.

Footage from the village of Gapanli, over 250 kilometres east of Baku, on the Azerbaijani side, showed Grad multiple missile launchers firing rounds from the field.

Shelling continues, says Nagorno-Karabakh

Officials in the self-proclaimed republic of Nagorno-Karabakh promptly disputed the reports of the unilateral ceasefire, saying that the town of Martakert has been heavily shelled all day despite Azerbaijan's pledge. David Babayan, spokesman for the Karabakh president, told The Associated Press on Sunday that they had not seen any signs that fighting was suspended: "The situation is quite the opposite."

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In this image made from video on Sunday, a Grad missile is fired by Azerbaijani forces in the village of Gapanli. Officials in Azerbaijan and the separatist region of Nagorno-Karabakh say fighting is persisting a day after the worst outburst of hostilities in nearly 20 years killed 30 soldiers. (Associated Press)

The defence ministry of Nagorno-Karabakh on Sunday also claimed to have restored control over a strategic area near the front line. It said Nagorno-Karabakh forces went on a counter-offensive around the village of Talish after Azerbaijani forces shelled their positions just before dawn. Two Karabakh troops were reported injured.

It also said Azerbaijan was using rockets, artillery and armour against the region.

Turkey takes sides

The self-proclaimed officials in Karabakh, however, said they will be ready to discuss a ceasefire with Azerbaijan as long as their respective positions on the ground are restored.

Armenia's deputy defence minister at a Sunday briefing with military attaches based in Yerevan said Armenia will be ready to send troops to Karabakh "if necessary."

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An Armenian volunteer is pictured here on Saturday the town of Askeran in the separatist Nagorno-Karabakh region, which has just seen one of the worst outburst of hostilities in nearly 20 years. (Hrayr Badalyan/PAN Photo via Associated Press)

Turkish President Recep Tayyip Erdogan vowed Sunday to back its ally Azerbaijan in the conflict, saying that the flare-up could have been avoided if "fair and decisive steps" had been taken.

"We pray our Azerbaijani brothers will prevail in these clashes with the least casualties," he said.

The unresolved conflict has been an economic blow to Armenia because Turkey has closed its border with Armenia.