Ukrainian President Volodymyr Zelensky said Saturday he would present Moscow a proposal for ending the war once it had been agreed by the international community.
He made the commitment in Switzerland during an address to an inaugural summit on peace in his country, attended by more than 90 countries, but not Russia.
Zelensky told the forum he hoped the summit would lay the groundwork for a "just" and "lasting" settlement with Russia.
"We must decide together what a just peace means for the world and how it can be achieved in a lasting way," he said.
"Then it will be communicated to the representatives of Russia, and so that at the second peace summit we can fix the real end of the war," he added.
Zelensky did not say if he was prepared to engage in talks with Russian President Vladimir Putin directly.
On the eve of the summit, Putin laid out his own conditions for ending the conflict.
He called on Ukraine to withdraw its troops from the south and east of the country and renounce its ambitions to join the NATO military alliance, conditions quickly dismissed by Zelensky.
"He is not calling for negotiations, He is calling for surrender," US Vice President Kamala Harris told Saturday's summit of Putin's demands.
Western leaders lined up to pledge support for Ukraine and stress the need for a settlement on Kyiv's terms.
German Chancellor Olaf Scholz said a ceasefire without "serious negotiations with a roadmap towards a lasting peace... would only legitimise Russia's illegal land grab."
European Commission chief Ursula von der Leyen insisted that "freezing the conflict today with foreign troops occupying Ukrainian land is not an answer.
"In fact, it is a recipe for future wars of aggression," she warned.
But some countries from outside Ukraine's traditional circle of partners stressed the need to give Russia a voice and criticised some Western sanctions targeting Moscow.
Kyiv would have to be prepared for a "difficult compromise" if it wanted to end the conflict, Saudi Foreign Minister Faisal bin Farhan Al-Saud told the conference.
And Kenya's President William Ruto blasted a recent G7 deal to offer a $50-billion loan to Ukraine secured against profits of frozen Russian assets.
"The unilateral appropriation of Russian assets is equally unlawful," Ruto said in his opening address, after calling Russia's invasion a "horrifying spectacle of carnage and devastation".
