By Dan Peleschuk and Yuliia Dysa

KYIV, Jan 7 (Reuters) - Ukraine's President Volodymyr Zelenskiy is seeking a new meeting with U.S. President Donald Trump as their officials revisited the two most problematic issues in peace talks aimed at ending Russia's war in Ukraine.

Kyiv is under U.S. pressure to secure peace quickly but wants security guarantees from allies and is pushing back on Russian demands to cede its eastern Donetsk region and give up control of the Zaporizhzhia nuclear power plant.

Speaking to reporters over WhatsApp on Wednesday, Zelenskiy said he wanted to meet Trump again soon to gauge his openness to a Ukrainian proposal that Washington provide security guarantees for more than 15 years in the event of a ceasefire.

He also urged Trump to step up pressure on Russia, which has been cool on the U.S.-backed peace push and is continuing its massive air attacks on Ukrainian cities and the country's energy grid.

"The Americans, in my view, are being productive right now; we have good results... They need to put pressure on Russia. They have the tools, and they know how to use them," Zelenskiy said.

The White House did not immediately respond to a request for comment on the suggestion of a new meeting between Zelenskiy and Trump.

Citing the U.S. operation to seize Venezuelan leader Nicolas Maduro, Zelenskiy suggested Washington could similarly move against Chechen leader Ramzan Kadyrov, a Vladimir Putin ally whose troops became known for their brutality in Ukraine.

"Maybe then Putin would see it and think twice," he said.

Talks in Paris this week produced commitments from Kyiv's allies to back up a ceasefire with guarantees such as a multinational troop presence.

But Zelenskiy said the expression of "political will" had yet to be translated into legally binding pledges backed by national parliaments.

MAJOR STUMBLING BLOCKS

Zelenskiy spoke as U.S. and Ukrainian officials in Paris discussed the matter of territory and the fate of the Zaporizhzhia plant , Europe's largest nuclear facility, which he described as the two thorniest issues in the talks.

Kyiv has refused to pull out of the industrialised Donetsk region, which Russia has failed to seize entirely despite occupying wide swathes of it. Zelenskiy has said the U.S. has floated the idea of a free economic zone there if Ukraine withdraws from the parts of the region that it still controls.

On Tuesday, U.S. and Ukrainian officials had already talked through "some ideas" to address the issue of territory. White House special envoy Steve Witkoff said "land options" had been discussed and that he hoped for compromise to be reached.

Any compromises on land should be put to a referendum for Ukrainians, Zelenskiy has previously said. According to an opinion poll last month, around three-quarters of Ukrainians are prepared for a deal that would freeze the current front line, but oppose ceding territory.

The U.S. has also proposed trilateral operation of the Zaporizhzhia plant, which Moscow captured in 2022 and connected to its own power grid, with an American chief manager, Zelenskiy said last month.

Kyiv has instead proposed joint Ukrainian-American use of the plant, according to Zelenskiy, with the U.S. itself determining how to use 50% of the energy produced.

(Writing by Dan PeleschukEditing by Hugh Lawson and Frances Kerry)