"Security guarantees will probably be 'unpacked' by our partners, and more and more details will emerge. All of this will somehow be formalised on paper within the next week to 10 days," Zelenskiy said at a press briefing after the meetings about ending the war in Ukraine on Monday.
Trump told Zelenskiy the US would help guarantee Ukraine's security in any deal to end Russia's war, though the extent of any assistance wasn't clear.
Zelenskiy was backed by the leaders of Britain, Germany, France, Italy, Finland, the European Union and NATO, who travelled to Washington to demonstrate solidarity with Ukraine and push for strong security guarantees for the country in any post-war settlement.
"It is important that the United States is sending a clear signal that it will be among the countries helping to co-ordinate and will also be a participant in the security guarantees for Ukraine," Zelenskiy said.
"I believe this is a major step forward."
Although a peace deal appeared far from imminent after the meetings in Washington, Zelenskiy said his meeting with Trump was his "best" so far.
Zelenskiy later added on social media platform X that Trump "supported a meeting at the level of leaders. Such a meeting is necessary to resolve sensitive issues".
He also said Ukraine was ready to meet with Russia in "any format" and that territorial issues would be discussed on a bilateral level with Russian President Vladimir Putin - but no dates have been scheduled.
"Come what may" Zelenskiy said he should meet Putin and start working out how to end the conflict, stressing that preconditions for talks from Kiev would be met by "one hundred demands" from Russia.
"The question of territories is something we will leave between me and Putin," Zelenskiy said.
He added that a part of security guarantees for Ukraine is a package of US weapons "which primarily includes aircraft, air defence systems", worth $US90 billion ($A138 billion.
"And we have agreements with the US president that when our export opens, they will buy Ukrainian drones. This is important for us."
Trump labelled the meetings "very good" and confirmed he was planning a meeting between Putin and Zelenskiy.
"At the conclusion of the meetings, I called President Putin, and began the arrangements for a meeting, at a location to be determined, between President Putin and President Zelenskiy," Trump posted on Truth Social, adding that US Vice President JD Vance, Secretary of State Marco Rubio and Special Envoy Steve Witkoff would make the arrangements.
Trump hosted Zelenskiy and European allies two days after Trump met with Putin in Alaska and months after a disastrous Oval Office meeting in February where Trump and Vice President JD Vance publicly criticised the Ukrainian leader.
While a peace deal appears far from imminent, European leaders urged Trump to insist that Putin agree to a ceasefire before any talks can advance.
Trump had previously backed that proposal but reversed course after meeting with Putin on Friday, instead adopting Moscow's position that any peace agreement be comprehensive.
Trump told reporters in the Oval Office he liked the concept of a ceasefire but that the two sides could work on a peace deal while the fighting continued.
"I wish they could stop, I'd like them to stop," he said.
"But strategically that could be a disadvantage for one side or the other."
German Chancellor Friedrich Merz and French President Emmanuel Macron both voiced support for a ceasefire as a prerequisite to any direct talks with Russia and Macron said European leaders would need to be involved in subsequent meetings as well.
"When we speak about security guarantees, we speak about the whole security of the European continent," he told Trump.
Trump and Zelenskiy's meeting was starkly different in tone from their previous Oval Office encounter, which ended when Trump and Vance publicly upbraided Zelenskiy for not being grateful enough.
Trump's team has said there will have to be compromises on both sides to end the conflict. But the president himself has put the burden on Zelenskiy, saying Ukraine should give up hopes of getting back Crimea, annexed by Russia in 2014, or of joining the NATO military alliance.
Zelenskiy has already all but rejected the outline of Putin's proposals from the Alaska meeting. Those include handing over the remaining quarter of its eastern Donetsk region, which is largely controlled by Russia. Any concession of Ukrainian territory would have to be approved by a referendum.
with dpa
