WEST PALM BEACH, Florida - A Kremlin envoy says peace talks on a US-proposed plan to end the nearly four-year Russia-Ukraine conflict were pressing on "constructively" in Florida.

"The discussions are proceeding constructively," Kirill Dmitriev, special envoy of Russian President Vladimir Putin, told reporters in Miami on Saturday. "They began earlier and will continue today, and will also continue tomorrow."

Dmitriev met with United States President Donald Trump's special envoy Steve Witkoff and Trump's son-in-law Jared Kushner, Russian state news agency RIA Novosti reported.

US Secretary of State Marco Rubio had said he might also join the talks.

The Miami meeting followed US talks on Friday with Ukrainian and European officials, the latest discussions of a peace plan that has sparked some hope of a resolution to the conflict. The officials reported progress on security guarantees for Kyiv, but it remains unclear if those terms will be acceptable to Moscow.

A Russian source told Reuters that any meeting between Dmitriev and the Ukrainian negotiators had been ruled out.

Ukrainian President Volodymyr Zelensky said on Saturday Ukraine would back a US proposal for three-sided talks with the US and Russia if it facilitated more exchanges of prisoners and paved the way for meetings of national leaders.

"America is now proposing a trilateral meeting with national security advisers — America Ukraine, Russia," Zelensky told journalists in Kyiv.

On Sunday, the Kremlin denied that such three-way talks were in the cards.

"At present, no one has seriously discussed this initiative, and to my knowledge, it is not in preparation," Putin's foreign policy adviser Yury Ushakov told reporters, according to Russian news agencies.

'Not improving'

In addition, Ushakov said changes made by the Europeans and Ukraine to US proposals for an end to the conflict did not improve prospects for peace.

"This is not a forecast," he was quoted as saying by Russian news agencies, though he said he had not seen the exact proposals on paper yet.

"I am sure that the proposals that the Europeans and Ukrainians have made or are trying to make definitely do not improve the document and do not improve the possibility of achieving long-term peace."

Meanwhile, Ukraine's top negotiator, Rustem Umerov, said his delegation had completed separate meetings in the United States with US and European partners who agreed to pursue their joint efforts.

"We agreed with our American partners on further steps and on continuing our joint work in the near future," Umerov wrote on Telegram of the discussions, adding that he had informed Zelensky of the outcome of the talks.

Rubio told reporters on Friday that progress has been made in discussions to end the conflict but there is still a way to go.

"The role we're trying to play is a role of figuring out whether there's any overlap here that they can agree to, and that's what we've invested a lot of time and energy and continue to do so," he said. "That may not be possible. I hope it is. I hope it can get done this month before the end of the year."

On the ground, a Russian missile strike on port infrastructure in Odesa in southern Ukraine killed eight people and wounded 27,Ukraine's emergency service said on Saturday.

The port was struck with ballistic missiles, said Oleh Kiper, the head of the Odesa region.

Moscow did not immediately acknowledge reports of the attack. The Russian Defense Ministry said on Saturday that over the previous day, it had struck unspecified "transport and storage infrastructure used by the Ukrainian armed forces", along with energy facilities and those supplying Kyiv's war efforts.

Elsewhere, Ukrainian drones hit a Russian oil rig, the military patrol ship Okhotnik and other facilities, Ukraine's General Staff said in a statement on Saturday. It said the ship was patrolling in the Caspian Sea near an oil and gas production platform. The extent of the damage was still being clarified, it said.

Agencies via Xinhua