Defence ministers attending a meeting of the "Coalition of the Willing" meeting at NATO on Thursday say plans are now "well developed" but that much more work needs to be done to define the scope of any post-peace deal mission and how many troops may be needed.
Ministers from 30 countries joined the meeting convened by France and the UK for operational discussions to set up a reassurance force for Ukraine that is meant to act as a deterrent against potential Russian aggression.
"Our planning is real and substantial. Our plans are well developed and we have clear objectives for Ukraine," UK Defence Secretary John Healey said in his opening statement.
The aim of the meeting, he added, was to "focus on how operational planning of the coalition could work, and how we make sure that we're fully prepared for the moment a peace agreement is reached, but we cannot jeopardize the peace by forgetting about the war and the daily reality for millions of Ukrainians continues".
The gathering comes after a delegation of French and British military officials travelled to Kyiv for meetings with Ukrainian President Volodymyr Zelenskyy, Defence Minister Rustem Umerov, and the country's military leaders to discuss planning.
French President Emmanuel Macron, who chaired a summit of leaders late last month on the issue, had said the force could be deployed in "strategic" towns in Ukraine and that the visit to Ukraine by military officials would seek to work out which locations would be best.
But Macron also said that not all of the 33 delegations at the summit had agreed to take part and that contribution would not be limited to air, land and sea forces in Ukraine but would also entail logistics and intelligence capacities.
Poland and Greece, for instance, have said they cannot provide troops to the force, citing the threats they face from Belarus and Turkey respectively.
Ministers arrivers at the meeting wouldn't be drawn to comment on how many troops could be sent to Ukraine and under what timeline.
Andris Sprūds, Latvia's defence minister, echoed Healey by saying that "we already see some move forward considerably" and that the countries participating all feel "a sense of urgency".
But, he added, the various countries' contributions will depend on the "parameters" of any possible peace deal. His small Baltic country, for instance, does not rule out sending boots on the ground in Ukraine provided its own defence along the border with Russia is not weakened.
The EU's top diplomat, Kaja Kalals, meanwhile said that the goal of the reassurance force - "is it deterrence, is it monitoring, is it peacekeeping?" - also needs to be determined to proceed forward.
Another key reservation for some countries, such as Italy, is over the US's participation.
Most of the countries in the coalition agree that a so-called "US backstop" is needed, with air protection and intelligence sharing among the assistance they hope to secure from Washington.
Macron and his British counterpart, Prime Minister Keir Starmer, have both met with US President Donald Trump and have been in regular contact with him since to keep him updated on the discussions at the European level. But Washington has so far refused to join such a coalition.
Finnish Defence Minister Antti Häkkänen on Thursday described the US as a "crucial player" that "must be involved somehow", while his Dutch counterpart said having Washington on board "is important".
"Of course, it is good if the US is very explicit about its support and backstop," Ruben Brekelmans also told reporters at NATO HQ, adding that it "really depends on the mission to what extent US involvement is needed".
The US has also stepped back from the Ukraine Defence Contact Group - otherwise known as the Ramstein group - which it used to chair under the previous administration of Joe Biden. Defence Secretary Pete Hegseth is not expected to take part in the group's next meeting on Friday, which should be attended by some 50 countries.
This article has been updated to add comments from ministers following their arrival at the meeting.
