French President Emmanuel Macron warned Friday that even if Ukraine's European allies decide to send Kyiv fighter jets they could not be sent in "the coming weeks".
"I'm not ruling anything out ... but that doesn't correspond to today's requirements," Macron said after an EU summit in Brussels attended by Ukraine's President Volodymyr Zelensky.
Russia has launched a renewed offensive in Ukraine's war-torn east and Zelensky came to London, Paris and Brussels this week looking for more advanced weapons for his forces.
Ukraine has a shopping list of western combat jets, long-range missiles and heavy tanks -- but is also facing critical shortages in more basic supplies like artillery shells.
Britain has offered to train Ukrainian pilots on Western jets, while Poland and Slovakia are considering sending more of the Soviet-designed Mig-29 fighters that Kyiv already uses.
But Ukraine's allies are nervous that deploying advanced Western fighter jets would provoke a further escalation by Moscow and risk open conflict between NATO and Russia.
Macron and the other EU leaders in Brussels hailed Zelensky as a hero and promised to stand by Ukraine until victory -- but they were cautious on his quest for fighter jets.
"It is essential the allies favour the most useful equipment" and "the fastest", Macron argued, citing the Caesar guns and the MAMBA medium-range surface-to-air defence system supplied by the France.
It may be necessary to step up delivery of artillery pieces and munitions to allow Ukraine to launch or resist ground offensives, he added, promising to "work on it in the coming days".
Agence France-Presse