Two French and two Armenian journalists have been injured in the South Caucasus separatist region of Nagorno-Karabakh amid fighting between Armenian and Azerbaijani forces.

The two Le Monde reporters were wounded in morning shelling in the town of Martuni, the newspaper said. Armenia’s Foreign Ministry said they were being taken to a hospital and accused Azerbaijan of bombarding the region.

A cameraman with the Armenia TV channel and a reporter with the Armenian 24News outlet were also injured in the Martuni shelling, Armenian officials said. It was unclear how badly the four journalists were hurt. A Russian journalist with the independent Dozhd TV channel was reported to have reached a bomb shelter safely.

Clashes broke out on Sunday in Nagorno-Karabakh, a region within Azerbaijan that has been controlled by ethnic Armenian forces backed by the Armenian government since the end of a separatist war a quarter of a century ago. Fighting has continued unchecked since then, killing dozens and leaving scores wounded. Armenian and Azerbaijani forces blame each other for continuing attacks.

The two ex-Soviet nations have been locked for decades in a conflict over Nagorno-Karabakh, where a separatist war was fought in the early 1990s, ending in 1994 – three years after the breakup of the Soviet Union. The 1,700 square mile enclave in the Caucasus Mountains, roughly the size of the US state of Delaware, lies 30 miles from the Armenian border.

Soldiers backed by Armenia occupy the region as well as some Azerbaijani territory outside of it.

The president of Azerbaijan said Armenia’s withdrawal from Nagorno-Karabakh was the sole condition to end the fighting. Armenian officials claim Turkey is involved in the conflict, allegedly sending fighters from Syria to the region and deploying Turkish F-16 fighter jets to assist Azerbaijani forces.

Turkey has publicly supported Azerbaijan in the conflict and said it would provide assistance if requested but denies sending in foreign mercenaries or arms.

Continued fighting in the turbulent region prompted calls for a ceasefire from around the globe and raised concerns of a broader conflict potentially involving other regional powers.

The office of French President Emmanuel Macron said he and Russian President Vladimir Putin discussed the issue in a phone call and both “share concern about the sending of Syrian mercenaries by Turkey to Nagorno-Karabakh”.

The Russian Foreign Ministry expressed concern over reports about “militants from illegal armed groups” from Syria and Libya being sent to the conflict zone in Nagorno-Karabakh. It did not provide further details, but in a statement urged the “leadership of the states concerned to take effective measures to prevent the use of foreign terrorists and mercenaries in the conflict.”

Mr Macron said he and Mr Putin urged restraint and agreed upon the need for a joint effort towards a ceasefire, as part of international mediation efforts for Nagorno-Karabakh led by Russia, France and the US.