President Joe Biden has said that the United States would not provide F-16 fighter jets to Ukraine, as Kyiv expands the list of weaponry it needs to be better able to drive Russia forces from occupied territories.
Fighting continued at key points along the long front as Russian forces sought to expand their hold on territory in the Donetsk region of eastern Ukraine.
The Kremlin-appointed Donetsk leader, Denis Pushilin, claimed Russian forces were advancing near Vugledar, a strategically valuable town southwest of Donetsk city.
"Now we can say that units have established positions in the eastern part of Vugledar, and work is also being carried out in the vicinity," Pushilin said, according to Russian news agencies.
But Kyiv rejected the claim, while conceding that the fighting there was tough.
"The enemy doesn't count its people and, despite numerous casualties, maintains a high intensity of attacks," Ukraine's President VolodymyrZelensky said late Sunday.
- Jets for Ukraine? -
At the White House, Biden said he was opposed to supplying American fighter jets to Ukraine.
"No," he said when asked by reporters at the White House if he was in favor of sending F-16s or others, now that the US, Germany and other countries have agreed to boost the Ukrainian arsenal by providing heavy battle tanks.
But European leaders said they were open to the idea, even if Ukraine has not yet formally requested advanced fighter aircraft from its allies for the war.
Analysts believe both Ukraine and Russia are gearing up for significant offensive movements in the coming months and Western aircraft could increase Kyiv's strength, with its own air force significantly depleted by 11 months of war.
French President Emmanuel Macron said on Monday he would not rule out giving fighter aircraft to Ukraine but warned against the risk of escalation in the conflict.
Macron had talks with Netherlands Prime Minister Mark Rutte, who has already floated the idea of sending Dutch F-16s to Ukraine.
"Nothing is excluded in principle," Macron said.
Any arms delivery "must not weaken the capacity of the French armed forces," he said, adding that France would have to be confident that the weapons would not be used to strike inside Russia, which could escalate the war.
"There is no taboo but it would be a big step," said Rutte.
- Artillery shells -
With Ukraine's supplies of artillery munitions heavily depleted, France and Australia announced Monday a deal to jointly produce 155 mm shells for Kyiv's forces.
"Several thousand 155 mm shells will be manufactured jointly," French Defence Minister Sebastien Lecornu said. "There are some unique capabilities that exist in Australia and some synergies that can be achieved by Australia and France working together in relation to the supply of this ammunition," said his Australian counterpart Richard Marles.
Meanwhile, in Seoul, NATO Secretary General Jens Stoltenberg asked South Korea to "step up" military support for Ukraine, suggesting it reconsider its policy of not exporting weapons to countries in conflict.
There is an "urgent need for more ammunition," Stoltenberg said.
It is "extremely important that President Putin doesn't win this war," he stressed.
- Iran-Ukraine strains -
Tehran on Monday summoned a Ukrainian diplomat to protest remarks made by an aide to Zelensky following the unattributed weekend strikes that targeted an Iranian defense industry site in Isfahan that reportedly produced drones.
"Explosive night in Iran -- drone and missile production, oil refineries," said MykhailoPodoliak in a tweet.
"War logic... bills the authors and accomplices strictly," he said, adding: "Ukraine did warn you."
Iran has been supplying attack drones to Russia for use against Ukraine.
Iran's foreign ministry said Ukraine's charge d'affaires in Tehran had been summoned to provide "an official and immediate explanation" for remarks it called "strange and biased."
The foreign ministry added in a statement that it hoped "such positions will not be repeated."