US negotiators have touted the idea of Ukraine withdrawing its remaining forces from the eastern Donbas region in exchange for Nato membership, Volodymyr Zelensky has said.
The Ukrainian president's comments on Saturday come after US envoys visited Moscow and an EU summit in Dublin as part of ongoing efforts to end the war between Russia and Ukraine.
Kyiv has long sought membership of the military alliance as a condition of any peace deal to deter future threats, while Russia has said another Nato member on its border was unacceptable.
Zelensky has also consistently said Ukraine was unwilling to give up sovereign territory, despite Moscow's demands for it to cede the Donbas.
"The Americans raised a question: 'What if Ukraine joins Nato? Would Ukraine withdraw from Donbas?' This was the first time this had been raised," Zelensky told reporters on Saturday.
He went on to say that if he received a proposal that contained security guarantees, no constraints on Ukraine's military and funds to rebuild the country, he would put it to a referendum.
US envoys Jared Kushner and Steve Witkoff travelled to the Irish capital on Thursday to meet Zelensky, after a round of talks with Russian President Vladimir Putin in Moscow the day prior.
Comments by both Putin and Kremlin officials suggest that Russia's position on the war has not shifted, and that Moscow's demands for territory and neutrality continue to far exceed what Ukraine is prepared to consider.
Moscow has previously proposed limits on the size of Ukraine's military, territorial concessions and Kyiv's guaranteed neutrality as conditions of a peace deal.
Ukraine has rejected these, arguing that such constraints would hamper its ability to stave off any future invasion.
There have, however, been recent signs the two can find common ground: last month, US First Lady Melania Trump was able to broker a temporary ceasefire in the Russian-occupied city of Oleshky to allow for evacuations and aid deliveries.
US officials had previously said that Ukrainian Nato membership was off the table.
Zelensky said on Saturday that the US proposal made him believe that "Nato is back on the agenda".
But he cautioned: "You have also heard Putin's signals, and this is an extremely difficult conversation."
Russia currently occupies roughly a fifth of Ukrainian territory, including most of the Donetsk and Luhansk regions that compose the Donbas.
Ceding the small portions of land Ukraine still controls there would be a small concession in practical terms, but would be symbolically significant for Kyiv because it would constitute an acceptance of the Donbas being Russian.
Zelensky has previously spoken of retaking Russian-controlled territory in four of Ukraine's regions, as well as the Crimean peninsula, which Moscow annexed in 2014.
