Fighting broke out on September 27 in the region, which is located within Azerbaijan and under the control of local ethnic Armenian forces. It is some of the worst in Nagorno-Karabakh and surrounding areas since the end of a war in 1994.
Armenian Defence Ministry spokeswoman Shushan Stepanian said intensive fighting was “taking place place along the entire front line” on Saturday and that Armenian forces had shot down three planes.
Azerbaijan's Defence Ministry denied any planes being shot down and said Armenian personnel had shelled civilian territory. Azerbaijan President Ilham Aliyev said his country's army ”raised the flag” in the town of Madagiz and taken seven villages.
Nagorno-Karabakh officials have said more than 150 servicemen on their side have died so far. Azerbaijani authorities haven't given details on their military casualties but said 19 civilians were killed and 55 more wounded.
Vahram Poghosyan, a spokesman for Nagorno-Karabakh's president, claimed Saturday on Facebook that intelligence data showed some 3,000 Azerbaijanis have died in the fighting. Armenian Defence Ministry spokesman Artsrun Ovannisian said later that 2,300 Azerbaijan troops were killed, about 400 of them in the last day.
With Azerbaijan not commenting on troop casualties, the statements could not be verified.
Nagorno-Karabakh was a designated autonomous region within Azerbaijan during the Soviet era. It claimed independence from Azerbaijan in 1991, about three months before the Soviet Union's collapse. A full-scale war that broke out in 1992 killed an estimated 30,000 people.
By the time the war ended in 1994, Armenian forces not only held Nagorno-Karabakh itself but substantial areas outside the territory's formal borders, including Madagiz, the village Azerbaijan claimed to have taken Saturday.
Several United Nations Security Council resolutions have called for withdrawal from those areas, which the Armenian forces have disregarded.
Aliyev said in a television interview the Armenians must withdraw from those areas before the latest fighting can stop.
In the interview with Al Jazeera, a transcript of which was distributed Saturday by the presidential press office, Aliyev criticized the so-called Minsk Group of the Organization for Security and Cooperation in Europe, which has tried to mediate a resolution of the Nagorno-Karabakh dispute.
One reason behind the current fighting is that “the mediators do not insist or exert pressure to start implementing the resolutions of the United Nations Security Council,” he said.
“We have no time to wait another 30 years. The conflict must be resolved now,” Aliyev said.
Armenia has repeatedly claimed over the past week that Turkey sent Syrian fighters to Azerbaijan and that the Turkish military is aiding Azerbaijan's.
“Turkey and Azerbaijan are pursuing not only military-political goals," Armenian Prime Minister Nikol Pashinian said Saturday in an address to his nation. “Their goal is Armenia, their goal is continuation of the genocide of Armenians.”
Some 1.5 million Armenians died in mass killings in Ottoman Turkey beginning in 1915, which Armenia and many other countries have labelled a genocide. Turkey firmly rejects that term, contends the total number of victims is inflated and says the deaths were the consequence of civil war.
Azerbaijan's Foreign Ministry released a statement Saturday alleging that thousands of ethnic Armenians from abroad were being deployed or recruited to fight for Armenia.
“Armenia and Armenian disapora organizations bear international legal liability for organizing these terrorist activities,” the statement said.