Rutte told reporters on the eve of the talks that "clearly" allies were discussing the plan which calls for ramped-up Western backing including an invitation to join NATO, and that it would "be on the table this week".

Unveiled earlier Wednesday, Zelensky's five-part plan for ending the Russian invasion cites an immediate offer of NATO membership as its first priority -- prompting a Kremlin warning that Kyiv was pushing the alliance towards "direct conflict" with Russia.

NATO countries have declared Ukraine to be on an "irreversible path" to membership, but the United States and Germany have led opposition to immediate entry, believing it would effectively put the alliance at war against nuclear-armed Russia.

Pressed on the question, Rutte reiterated NATO's position, saying: "I cannot today now exactly sketch out what the path will be, but I am absolutely confident that in the future, Ukraine will join us."

After pushing back Russian troops at the start of the invasion in February 2022, Kyiv is now facing mounting pressure to find an exit strategy as its troops suffer battlefield losses and Moscow intensifies its strikes on infrastructure.

Rutte called the plan unveiled Wednesday "a strong signal from Zelensky" -- while cautioning: "That doesn't mean that I here can say I support the whole plan."

"The plan has many aspects and many political and military issues we really need to hammer out with Ukrainians to understand what is behind it, to see what we can do, what we cannot do," he added.

"In the meantime we will continue massive military aid moving into Ukraine. Russia has to understand we will keep on doing that as long as they continue the war effort."

Zelensky is due to present his plan in full at an EU leaders' summit also taking place Thursday in Brussels, across town from the NATO gathering.