(CNN)Russia, France and the United States have called for an immediate and unconditional ceasefire in the conflict over Nagorno Karabakh, an Armenian enclave in Azerbaijan.
US Secretary of State Mike Pompeo, Russian Foreign Minister Sergey Lavrov and French Foreign Minister Jean-Yves Le Drian, issued a statement Monday condemning bloodshed "in and outside of the Nagorno Karabakh zone."
Issued at the end of another day -- the eighth -- of missile and rocket attacks against civilian populations, the joint statement also warned that attacks allegedly targeting civilian centers "constitute an unacceptable threat to the stability of the region."
Nagorno Karabakh is inside Azerbaijan's borders but has de facto independence and an Armenian majority. Officials there said Monday that a further 21 lives had been lost in fighting.
Meanwhile, Azerbaijan's prosecutor-general's office said one woman had been killed in the town of Barda and in total 25 civilians had been killed with 127 injured since the fighting erupted.
Authorities in Nagorno Karabakh said that its capital Stepanakert came under intense rocket fire Monday.
One official in Nagorno Karabakh posted video of the damage and posted on Twitter: "Look what distructions Azerbaijan did only today in capital #Stepanakert of #Artsakh/#Karabakh w/ heavy missiles. Schools, civilian objects, residential buildings were at intentional target. Isn't it war crime & crime against humanity?"
The Azerbaijani Defense Ministry said the city of Ganja, the second largest in Azerbaijan, came under attack for the second consecutive day. A civilian contacted by CNN on Monday evening said "My family decided to send children to other regions as they are in panic. All of my relatives are currently living in the basement."
Earlier, the Azerbaijani authorities said several towns and cities came under attack Monday, including Agjabadi, Beylagan, Barda and Tartar.
The confrontation over Nagorno Karabakh's status first erupted after the breakup of the Soviet Union in the 1990s, when the region declared independence from Azerbaijan, sparking a violent conflict.
Armenia backed Nagorno Karabakh, which established a de facto independence that is not internationally recognized.
Turkey's role in the conflict has become a subject of bitter dispute. Armenia's president, Armen Sarkissian, told CNN that he's asked the leaders of many countries to put pressure on Turkey to "stop interfering" in the region.
Sarkissian told CNN's Connect the World that Turkish interference in supporting Azerbaijan is "taking the conflict an order up in magnitude" and "creating something that will eventually become another Syria of the Caucasus."
"My plea is Turkey will be restrained with the help of Russia, US and France, then [we] will have a chance of a ceasefire, further, negotiations and then we will have a chance to go back to the negotiation table," he said.
Turkey has denied involvement in the conflict. Turkish Defense Minister Hulusi Akar said Monday: "Armenia is committing a war crime by targeting civilians. Everyone should know this."
The President of Azerbaijan, Ilham Aliyev, insisted Turkey was an important player in the region and told Turkish state broadcaster TRT: "Turkey surely must stay involved in the resolution of the conflict."
In a joint news conference with Turkey's Foreign Minister Monday, NATO Secretary-General Jens Stoltenberg said: "I expect Turkey to use its considerable influence to calm tensions."
"We should support all efforts to find a peaceful negotiated solution because there is no military solution to the situation in and around Nagorno Karabakh," Stoltenberg said.