BAKU/YEREVAN -- Armenia and Azerbaijan have exchanged blame for the collapse of a U.S.-brokered cease-fire as a month-long war over the separatist Nagorno-Karabakh region intensified near the border with Iran.
U.S. Secretary of State Mike Pompeo called on the leaders of Azerbaijan and Armenia on October 27 to abide by the cease-fire, which collapsed minutes after it was meant to go into effect the day before.
In separate phone calls with Armenian Prime Minister Nikol Pashinian and Azerbaijani President Ilham Aliyev, Pompeo "pressed the leaders to abide by their commitments to cease hostilities and pursue a diplomatic solution to the Nagorno-Karabakh conflict," the State Department said.
He also told the two leaders that "there is no military solution to this conflict," the State Department said.
Fighting was reported along several parts of the front line on October 27, with heavy clashes reported in the southern sector near the border with Iran.
Armenia accused Azerbaijan of using drones and artillery to strike border guard positions along its internationally recognized border in the southeast near Iran, compelling Armenian forces to strike back.
Azerbaijan denied violating the cease-fire in the area, accusing Armenian forces of firing mortars at its positions in Zangilan, Khojavend, Fizuli, and Gubadli on the southern front near the border with Iran.
Armenian Defense Ministry official Artsrun Hovhannisian said in a news conference late on October 26 that ethnic Armenian forces had given up the settlement of Gubadli, which lies south of the enclave and just seven kilometers from the Armenian border.
He said the settlement was given up "to avoid unnecessary losses," but the situation was "not critical."
Meanwhile, the head of Karabakh’s Armenia-backed defense forces, Lieutenant General Jalal Harutiunian, was replaced after reportedly being wounded in action.
Azerbaijan also accused Armenian forces of shelling the Azerbaijani town of Tartar and adjacent villages in the north.
"Armenian armed forces during the day on October 26 and overnight into October 27 fired at the positions of Azerbaijani Army units in different directions at the front and at our settlements near the front line with various weapons," the Azerbaijani Defense Ministry said in a statement.
Pashinian said the cease-fire had collapsed.
"I would like to state that the efforts of the international community, this time brokered by the United States, to establish a cease-fire, have failed. As a result of continuous shelling by Azerbaijan, civilians were killed and wounded in Artsakh (the Armenian name for Nagorno-Karabakh) today," Pashinian said on Twitter on October 27.
Meanwhile, the Azerbaijani Defense Ministry on October 27 claimed it was Armenia that has failed to comply with the humanitarian cease-fire.
"Armenian armed forces during the day on October 26 and overnight into October 27 fired at the positions of Azerbaijani army units in different directions at the front and at our settlements near the front line with various weapons. The fighting continued mainly in the frontline directions of Khojavend, Fizuli, and Gubadli," the ministry said in a statement, adding Azerbaijani forces had fought off the attacks.
The cease-fire was announced in a joint statement from the U.S. State Department and the two governments on October 25 -- the third attempt to establish a pause in the hostilities that broke out on September 27.
Two previous Russian-brokered cease-fires also collapsed soon after being agreed upon.
Ethnic tensions in the region between Christian Armenians and their mainly Muslim neighbors have flared in Nagorno-Karabakh for decades.
Under international law, Nagorno-Karabakh is recognized as part of Azerbaijan, but the ethnic Armenians, who make up the vast majority of the population, reject Azerbaijani rule. They have been governing their own affairs, with support from Armenia, since Azerbaijan's troops were pushed out of the breakaway region in a war in the 1990s.
Azerbaijani President Ilham Aliyev said in an address to the nation on October 26 that Azerbaijan wanted to resolve the conflict over Nagorno-Karabakh either by political or military means.
He also reiterated a demand that that Nagorno-Karabakh be returned to Azerbaijan along with seven surrounding districts controlled by Armenian forces.
The United States, France, and Russia -- co-chairs of the Minsk Group of the Organization for Security and Cooperation in Europe (OSCE) -- said its foreign ministers would meet on October 29 in Geneva to discuss the Nagorno-Karabakh issue.
The Minsk Group, formed to mediate the conflict, said the meeting would "discuss, reach agreement on, and begin implementation, in accordance with a timeline to be agreed upon, of all steps necessary to achieve a peaceful settlement of the Nagorno-Karabakh conflict."
Turkey has demanded a bigger role in the mediating body.
At least some 1,000 people have been reported killed since fighting erupted on September 27, raising fears of a wider conflict in the South Caucasus drawing in NATO member Turkey, which is an ally of Azerbaijan, and Russia, which has a military pact with Armenia.
Armenian forces and the Azerbaijani's military claim to have inflicted devastating losses on each other.
But reports from the opposing sides are often contradictory and hard to verify.
Russian President Vladimir Putin said on October 22 that Moscow believes nearly 5,000 people have been killed in the latest fighting.