Putin's invitation came as there appeared to be no end in sight for nearly two weeks of fighting between Azerbaijan and ethic Armenian separatists that has claimed hundreds of lives.

"The foreign ministers of Azerbaijan and Armenia are being invited to Moscow on Friday, Putin said in a statement released by the Kremlin.

"The President of Russia is issuing a call to halt the fighting in the Nagorno-Karabakh on humanitarian grounds in order to exchange dead bodies and prisoners," the Kremlin added.

Yerevan has so far ruled out any talks between the two countries' top diplomats as long as clashes are ongoing.

Earlier talks were held in Geneva but expectations were low and no statements were likely from the negotiations which were being conducted behind closed doors - and without Armenian participation.

Azerbaijan's Foreign Minister Jeyhun Bayramov was to meet diplomats from France, Russia and the United States, who make up the "Minsk Group" that has sought a solution to the Karabakh conflict since the 1990s.

Armenia on Thursday accused Azerbaijan of shelling a historic cathedral in Nagorno-Karabakh.

Armenia said several journalists were injured in strikes on the cathedral after an initial bombardment left rubble strewn across the floor, pews knocked over and a layer of dust coating the interior from parts of the building's limestone walls that had been hit.

"There is no military, nothing strategic here, how can you target a church?" said local resident Simeon, who lives nearby.

Azerbaijan and Armenia are locked in bitter fighting over Nagorno-Karabakh, an Azerbaijani region controlled by Armenians who declared an unrecognized breakaway state after the fall of the USSR and emerged victorious from the war that followed.

Hundreds including civilians have been killed in the current fighting, the worst since a 1994 ceasefire, with both sides doubling down on entrenched positions over who should control the region.

Defense officials in Azerbaijan and Armenia said fighting continued into Thursday, with both sides claiming to have inflicted heavy losses and accusing the other of shelling civilian areas.

There was a gaping hole in the roof of the Ghazanchetsots (Holy Savior) Cathedral, AFP journalists reported, after Armenia's defense ministry accused Azerbaijan of targeting a cherished site for the Armenian Apostolic Church.

A section of the cathedral's metal roof collapsed and fell to the ground outside.

Baku denied its forces were behind the first attack, saying that unlike Armenia, "the Azerbaijani army does not target historical, cultural, or especially religious, buildings and monuments."

Explosions and sirens sounded in Nagorno-Karabakh's regional capital Stepanakert as the city continued to face regular shelling early Thursday, AFP journalists said.

Heavy bombardments have leveled many homes since fighting erupted late last month and Stepanakert is pockmarked with unexploded ordnance and wide craters from shelling.

Alongside the new bombardments in Stepanakert, Azerbaijan said Armenian shelling on several villages near the frontline had left people dead and wounded.