Russia’s top diplomat on Wednesday said the country would insist on being a part of any future security guarantees for Ukraine, a condition that European and Ukrainian officials widely see as absurd.

It was the clearest sign yet that enormous gaps remain in the negotiations over a possible end to Russia’s invasion. And it added to the uncertainty over how a European effort to rally a “coalition of the willing” to protect a postwar Ukraine, possibly with Western soldiers stationed inside the country, would fit into President Trump’s plans for a peace deal with President Vladimir V. Putin of Russia.

“Seriously discussing issues of ensuring security without the Russian Federation is a utopia, a road to nowhere,” Russia’s foreign minister, Sergey V. Lavrov, told reporters in Moscow after a meeting with his Jordanian counterpart.

Kyiv’s supporters largely dismiss the idea that Russia could be a part of ensuring Ukraine’s future security, given that it launched its military intervention there in 2014 and its full-scale invasion in 2022. But Mr. Lavrov signaled that Mr. Putin had not budged from his insistence on having a decisive say over Ukraine’s future sovereignty as part of any peace deal.

“We cannot agree that now it is proposed that security issues, collective security, be resolved without the Russian Federation,” Mr. Lavrov said. “This will not work.”

The Trump administration has trumpeted a breakthrough in talks with Russia this month, claiming that Mr. Putin had accepted a proposal for the West to provide security guarantees for Ukraine as strong as Article 5 of the NATO charter, which stipulates that an attack on one alliance member is considered an attack on all.