Armenia and Azerbaijan were due to hold their first high-level talks on Friday after nearly two weeks of clashes over the disputed Nagorno-Karabakh region, with hopes rising that a ceasefire could be brokered in Moscow.

France, which along with Russia and the United States is part of a group mediating the two countries' long conflict, said there was a chance of a breakthrough but it was far from certain.

"We are moving towards a truce tonight or tomorrow but it's still fragile," President Emmanuel Macron's office said in a statement to AFP.

Armenian and Azerbaijani defence officials said heavy clashes continued overnight and reported further civilian deaths, after Putin announced the meeting in Moscow late Thursday and appealed for a ceasefire on humanitarian grounds.

Azerbaijan's President Ilham Aliyev has repeatedly said there would be no halt to fighting until Armenian troops withdraw and vowed to continue the intervention until his army captured all of Karabakh.

Russia's foreign ministry said on Friday the two countries' top diplomats would hold talks in Moscow from 1200 GMT.

Renewed fighting over Karabakh -- an ethnic Armenian region of Azerbaijan that broke from Baku's control in a devastating war in the early 1990s -- has claimed some 400 lives and forced thousands of people from their homes.

Fledgeling mediation efforts

The heavy clashes erupted late last month, with both sides blaming the other for the biggest outbreak in violence since a 1994 ceasefire left the status of Karabakh in limbo.

The region's declaration of independence has not been recognised by any country -- even Armenia -- and the international community regards it as part of Azerbaijan.

The Kremlin said late on Thursday that following a series of calls with Armenian Prime Minister Nikol Pashinyan and Aliyev, Putin had invited their foreign ministers to Moscow and called for an end to hostilities "in order to exchange dead bodies and prisoners".

Previous diplomatic efforts to find a lasting solution to the decades-old stalemate have faltered.

Putin's announcement of talks in Moscow came shortly after international mediators from France, Russia and the United States launched their first efforts to resolve the fighting in Geneva.

The countries make up the "Minsk Group" that has sought a solution to the Karabakh conflict for decades but have failed to stop sporadic outbreaks of fighting.

The negotiations in Geneva went ahead without Armenia, which refused to participate if the fighting was ongoing, and there were no public statements following the closed-door talks.

Mounting civilian toll

Pashinyan on Friday said his country was "ready for the resumption of the peace process", while Russian Prime Minister Mikhail Mishustin during a visit to Yerevan said Russia was prepared to help bring about peace.

Since the fighting restarted both sides have accused the other of shelling areas populated by civilians and thousands of people have been displaced by the clashes.

The administrative centre of the disputed region, Stepanakert, is dotted with wide craters and unexploded ordnance following days of shelling.

Armenia accused Azerbaijan on Thursday of hitting the iconic Ghazanchetsots (Holy Saviour) Cathedral leaving a gaping whole in its roof and several journalists injured.

Armenia's rights ombudsman Artak Beglaryan told AFP this week that the renewed fighting has displaced around half of Karabakh's 140,000 residents and forced some 90 percent of its women and children from their homes.

Dozens of civilians have been confirmed killed and the Armenian side has acknowledged 350 military deaths, while Azerbaijan has not admitted to any fatalities among its troops.

Turkey's strong backing for Azerbaijan has sown fears in the West that the conflict could spiral into a full-blown war embroiling Ankara with Moscow, which has a military treaty with Armenia.

Putin and Macron are among the world leaders to denounce the reported deployment of pro-Turkish fighters from Syria and Libya to Karabakh and Iran this week warned of "terrorists" who had joined the conflict from abroad.