Armenian prime minister says his country faces ‘decisive moment’ as fighting between Armenian and Azeri forces intensifies in Nagorno-Karabakh.

Armenian and Azerbaijani forces have been engaged in intense fighting over the breakaway Nagorno-Karabakh region, scuttling diplomatic efforts to reach a ceasefire to end the latest conflict that has killed hundreds of people.

Shushan Stepanyan, spokeswoman for the Armenian defence ministry, said on Saturday that Azerbaijan had launched a new large-scale offensive, which was repelled by Armenia-backed forces who then launched a counter-push.

“Heavy fighting is ongoing on other flanks,” she wrote on Facebook.

Meanwhile, Azerbaijan’s defence ministry said its troops had destroyed a large amount of military equipment belonging to the Armenian military.

“During the present day, the troops of the Azerbaijani army, successfully advancing in the intended directions, took possession of new strongholds and carried out a clean-up of the territory from the enemy,” the ministry said early on Saturday.

Nagorno-Karabakh is controlled by ethnic Armenians backed by Armenia and has been the subject of several United Nations resolutions calling for an end to the occupation of Azeri lands.

The leader of the breakaway province, Arayik Harutyunyan, said he was heading to the front and that the “final battle” for the region had begun, while Armenian Prime Minister Nikol Pashinyan said his nation was facing a historic threat.

“We are facing possibly the most decisive moment in our millennia-old history,” Pashinyan said in an address to the nation on Saturday. “We all must dedicate ourselves to a singular goal: Victory.”

World powers have been calling for a ceasefire since Sunday when fighting over the region, which is officially part of Azerbaijan, broke out.

On Friday, Armenia’s foreign ministry said it was prepared to work with international mediators France, Russia and the United States to reach a ceasefire with Azerbaijan. While the three countries called for an end to hostilities, Turkey has staunchly supported its ally Azerbaijan and has repeated that what it called Armenian “occupiers” must withdraw.

“Superficial demands for an immediate end to hostilities and a permanent ceasefire will not be useful this time,” Mevlut Cavusoglu, Turkey’s foreign minister, was quoted as saying by Turkish state-run Anadolu news agency.

Both Azerbaijan and Turkey have repeatedly denied the involvement of Turkish forces in the fighting, as well as assertions by Armenia, Russia and France that Syrian rebels are fighting on the Azeri side.

Azerbaijan has also hit back, saying ethnic Armenians from the diaspora had been deployed or were on their way to operate as “foreign terrorist fighters” on the ethnic Armenian side.

Armenian sources have put the death toll from fighting in the region, where about 145,000 people live, at more than 200, while Azerbaijan most recently said that 19 civilians had been killed and 60 wounded.

Al Jazeera’s Bernard Smith reporting from  Stepanakert, the main city in Nagorno-Karabakh, said “the mood has darkened considerably over the last 24 hours.”

“That is because the city has been hit twice now with a series of attacks of large scale weaponry in two episodes, and that is the first time that this has happened here since the war ended in 1994,” he said. “We’ve seen more women and children trying to leave the town and more civilians sheltering in bunkers.”

Meanwhile, Al Jazeera’s Sinem Koseoglu, reporting from the Azerbaijani town of Barda, said people displaced by the fighting were sheltering in public buildings such as schools.

“There are no places that they can stay, that’s why most of the public buildings are spared for the internally displaced,” she said. “[Up to] five families sharing one room, sharing one bathroom; they are saying they didn’t have anything with them, except for the clothes and their shoes, and they are waiting to go back when the attacks finish.”

In an interview with Al Jazeera, Pashinyan said Armenia is the guarantor of security in Nagorno-Karabakh.

“Azerbaijan launched a direct attack on Nagorno-Karabakh and Armenia has certain obligations to provide the security for the region,” the prime minister said.

“The September 27 Azerbaijan offensive began with shelling of civilian settlements and this is a fact we need to acknowledge. When there is an attack, the very first task is to protect from that aggression after which only it is possible to talk about negotiations.”

For his part, President of Azerbaijan Ilham Aliyev said Armenia has not been interested in peace for the past three decades, after ethnic tensions increased following the collapse of the Soviet Union.

“They want to occupy our lands forever,” he told Al Jazeera’s Koseoglu. “If Armenia demonstrated goodwill and acted in compliance with many international resolutions, the conflict would have been resolved long ago.”

Azerbaijan and Armenia previously fought a war over Nagorno-Karabakh in the late 1980s and early 1990s as they transitioned into independent countries amid the collapse of the Soviet Union.

The war, which ended with a fragile peace treaty in 1994, is estimated to have killed tens of thousands of people, including more than a thousand civilians.

Armenia says it was Azerbaijan that reopened the conflict by launching a major offensive on September 27, while Baku says it was forced to respond to provocations by the other side.