On the fourth day of fighting, Azerbaijan and the ethnic Armenian enclave of Nagorno-Karabakh accused each other of shelling along the line of contact that divides them in the volatile South Caucasus.
Dozens have been reported killed and hundreds wounded in fighting since Sunday that has spread far beyond the enclave's borders, threatening to spill over into all-out war between the former Soviet republics of Azerbaijan and Armenia.
The re-eruption of one of the "frozen conflicts" from the collapse of the Soviet Union has raised concerns about stability in the South Caucasus, a corridor for pipelines carrying oil and gas to world markets, and raised fears that regional powers Russia and Turkey could be drawn in.
Some of Turkey's NATO allies are increasingly alarmed by Ankara's stance on Nagorno-Karabakh, a breakaway region inside Turkey's close ally Azerbaijan that is run by ethnic Armenians but is not recognized by any country as an independent republic.
Echoing remarks by President Tayyip Erdogan, Foreign Minister Mevlut Cavusoglu said on Wednesday Turkey would "do what is necessary" when asked whether Ankara would offer military support if Azerbaijan requested it.
Azerbaijan's president, Ilham Aliyev, later thanked Turkey for its support but said his country did not need military assistance. Fighting would cease if Armenian forces immediately "leave our lands," he said.
Cavusoglu also said French solidarity with Armenia amounted to supporting Armenian occupation in Azerbaijan.
French President Emmanuel Macron, whose country is home to many people of Armenian ancestry, hit back during a visit to Latvia. He said France was extremely concerned by "warlike messages" from Turkey "which essentially remove any of Azerbaijan's inhibitions in reconquering Nagorno-Karabakh."
"And that we won't accept," he said.
Paris has said it wants the Minsk Group - which is led by Russia, France and the United States and mediates between Armenia and Azerbaijan - to discuss the fighting. European Union leaders will also discuss the conflict at a summit this week, a German government source said.
NEW REPORTS OF FIGHTING
Nagorno-Karabakh, a mountainous enclave, broke away from Azerbaijan in the 1990s in a war that killed an estimated 30,000 people and displaced hundreds of thousands.
In Wednesday's clashes, Armenian media said three civilians had been killed and several wounded by shelling in the town of Martakert in Nagorno-Karabakh.
One person was killed and three wounded by Armenian fire on the town of Horadiz in southern Azerbaijan, the Azeri Prosecutor's office said, bringing the total number of Azeri civilians killed to 15 since fighting began on Sunday.
Azerbaijan released footage showing grey smoke rising from inside Nagorno-Karabakh as it was pounded by Azeri artillery. Photographs taken in the Azeri town of Terter showed people taking cover in dug-outs, and damaged buildings which residents said had been hit by Armenian shells.
Azerbaijan said ethnic Armenian forces attempted to recover lost ground by launching counter-attacks in the direction of Madagiz, but Azeri forces repelled the attack.
Armenia said the Azeri army had been shelling the whole front line during the night and two Azeri drones were shot down over Stepanakert, Nagorno-Karabakh's administrative center. It was not possible to independently confirm the report.
Armenian Prime Minister Nikol Pashinyan, who spoke to Russian President Vladimir Putin on Tuesday, said he was not considering asking for Russia's help at this point under a post-Soviet security treaty, but did not rule out doing so.
The Kremlin said Russia's military was closely following developments.
Armenia says one of its SU-25 warplanes was shot down by a Turkish fighter jet on Tuesday but Turkey and Azeri officials denied this