A man walks in front of a house damaged in shelling during the ongoing conflict between Armenia and Azerbaijan. AFP

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 reporters.

Armenian and Azerbaijani defence officials said heavy clashes continued overnight and reported further civilian deaths, after Putin announced the meeting in Moscow late on 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.

People stand near a hole outside a house damaged in shelling. AFP

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.

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".