French President Emmanuel Macron said leaders of the coalition backing Ukraine would meet again next week, hoping to finalise plans to secure a potential truce in the war with Russia.

The huddle in Paris with Ukrainian President Volodymyr Zelensky will be the latest in a series of high-stakes gatherings and will come after Kyiv and Moscow hold talks in Saudi Arabia with the United States on Monday.

Macron's announcement on Thursday came after London played host to the latest discussions of military top brass from the so-called "coalition of the willing" around Ukraine.

British Prime Minister Keir Starmer said plans on policing a possible ceasefire were "coming together" as US President Donald Trump forges ahead with Russia on ending its war on Ukraine.

Macron - who along with Starmer has said he is willing to deploy troops to Ukraine - said the meeting next Thursday will be a chance to "fine-tune" work on ensuring any truce is durable.

Meanwhile, Zelensky told an EU summit that "nothing had changed" as Moscow has kept up bombardments despite agreeing with Trump to halt strikes on Ukraine's energy system.

Zelensky said Russian President Vladimir Putin must "stop making unnecessary demands that only prolong the war", calling on the EU to ramp up arms deliveries and keep sanctions in force.

EU leaders vowed in a joint declaration, which was agreed without the support of Russia-friendly Hungary, to step up military support despite Moscow's demands for foreign support to stop.

But they stopped short of endorsing a request from Zelensky to give Kyiv US$5.4 billion for artillery shells, in the face of opposition from France and Italy.

In Norway, Zelensky said Ukrainian and US officials would meet in Saudi Arabia on Monday to build on US-led efforts to secure an end to the war with Russian, now grinding into its fourth year.

The Kremlin had earlier confirmed Russian officials would also hold talks with the US side in Saudi Arabia on the same day.

Zelensky and Putin both held talks with Trump this week, and have indicated they are prepared to halt attacks on energy infrastructure for 30 days. (AFP)