A proposed peace plan for Ukraine led by the United States has been met with anguish by many Ukrainians, who fear a post-war amnesty for Russian forces would erase accountability for alleged atrocitie

Asked later on Sunday whether the president still considered the Ukrainians "ungrateful," Rubio said he believed Trump was now "quite pleased" with progress at the negotiating table.

What happens to territory coveted by the Kremlin but not seized by Moscow’s troops during the war is a major sticking point in any peace deal.

The Russian attack followed talks between U.S. and Ukraine representatives in Geneva on Sunday about a U.S.-Russia brokered peace plan.

The U.S. and Ukraine said they had created an "updated and refined peace framework" to end the war with Russia that apparently modified an earlier plan drafted by the Trump administration which Kyiv and its allies saw as too sympathetic to Moscow.

As the US and Ukrainian delegations met in Geneva on Sunday, a Russian drone attack on Kharkiv killed four people, the city's mayor said.

Ukraine faces a Thursday deadline to adopt a peace plan presented by the U.S. with input from Russia. Discussions over the past few days suggest a Thanksgiving truce is unlikely. The main parties—between the Ukraine, Russia, the U.S., and Europe—remain divided over the key elements of the plan.

The United States and Ukraine pressed on with talks in Switzerland on Monday to come up with a mutually acceptable peace plan, after agreeing to modify a U.S. proposal that Kyiv and its European allies saw as a Kremlin wish list.