Azerbaijan on Wednesday vowed to pursue military action against Armenian separatists in the breakaway Nagorny Karabakh region until a full Armenian withdrawal from the disputed territory.

Armenian and Azerbaijani forces are engaged in the heaviest fighting in years over Karabakh, an ethnic Armenian province that broke away from Azerbaijan in the 1990s during the collapse of the Soviet Union.

The long-simmering conflict erupted on Sunday with both sides blaming each other for the outbreak of violence.

“We only have one condition: Armenian armed forces must unconditionally, fully, and immediately leave our lands,” Azerbaijani President Ilham Aliyev said in televised remarks.

If “the Armenian government fulfils the demand, fighting and bloodshed will end, and peace will be established in the region,” he added.

Earlier today, Azerbaijan's foreign ministry said in a statement that Baku was “resolutely determined to continue the counter-offensive operation until its sovereignty and territorial integrity is fully restored [...] (and) we clearly see the Armenian troops leaving the territory of Azerbaijan”.

On Wednesday, Armenia and Azerbaijan rejected international calls for a halt to fighting and negotiations.

Nearly 100 people are confirmed to have died in the flare-up and both sides are claiming to have inflicted heavy losses on opposing forces.

France expresses solidarity with Armenia

Meanwhile, France’s president voiced solidarity with Armenia amid its conflict with Azerbaijan over Armenian-occupied Upper Karabakh.

Claiming that it was Azerbaijan last weekend that started the conflict, Emmanuel Macron called on Azerbaijan and Armenia to end the conflict unconditionally, adding that he had discussed this issue with Armenian Prime Minister Nikol Pashinyan and Azerbaijani President Ilham Aliyev.

“I wanted these attacks to end. I explicitly condemned these disproportionate attacks,” he said in a news conference during a visit to Latvia.

“Something has been happening since July,” he added, evidently referring to the killing of three Azerbaijani soldiers and the wounding of four others when Armenia launched a border attack on July 12.

“It was determined that the attacks on Sunday came from Azerbaijan,” claimed Macron, adding: “Both sides must comply with the cease-fire.”

Border clashes broke out early on Sunday when Armenian forces in Upper Karabakh, or Nagorno-Karabakh reportedly targeted Azerbaijani civilian settlements and military positions, leading to multiple casualties.

He said he would also discuss the issue with United States President Donald Trump and Russian President Vladimir Putin.

“I have noticed the political statements made by Turkey [in favour of Azerbaijan], which I find to be inconsiderate and risky,” said Macron, a frequent critic of Turkey.

“France is concerned by the warlike messages from Turkey which is in favour of Azerbaijan’s reconquering Nagorno-Karabakh. And that we won’t accept it,” he added, not mentioning that the region is internationally recognised as belonging to Azerbaijan.

Macron said that Armenia's sovereignty and people should be respected, urging against any statements that would raise tensions.

International pressure for a ceasefire has mounted as fears grow that the conflict could escalate into all-out war.

Karabakh's declaration of independence from Azerbaijan sparked a war in the early 1990s that claimed 30,000 lives, but it is still not recognised as independent by any country, including Armenia.