BERLIN, Dec. 15 (Xinhua) -- Ukrainian President Volodymyr Zelensky on Sunday indicated willingness to compromise on NATO membership in pursuit of a peace settlement, but rejected any territorial concession.

After five-hour talks in Berlin with a U.S. negotiating team led by White House special envoy Steve Witkoff and U.S. President Donald Trump's son-in-law Jared Kushner, Zelensky said he would comment on the talks once they are completed on Monday, when additional European leaders are set to join the discussions.

Witkoff said on social media that "a lot of progress" had been made during the discussions.

Before the meeting, Zelensky said Ukraine could suspend its bid to join NATO in exchange for Western security guarantees to prevent renewed conflict with Russia if a peace agreement were reached. At the same time, he rejected proposals from the Trump administration suggesting Ukraine should give up some territories currently under its control.

He said that Ukraine stands ready to agree on security guarantees based on NATO Article 5 as a part of a compromise in the peace process, the Ukrinform news agency reported.

"From the very beginning, Ukraine's desire was to join NATO, these are real security guarantees. Some partners from the United States and Europe did not support this direction," he told reporters.

"Article 5-like guarantees from the United States and from European partners, as well as from other countries ... would provide an opportunity to prevent another arrival of Russian troops," Zelensky said, adding, "It is already a compromise on our part."

He said on social media that "Ukraine needs peace on dignified terms, and we are ready to work as constructively as possible. The coming days will be filled with diplomacy. It is critically important that it delivers results."

He also criticized a U.S.-proposed plan to establish a "free economic zone" in parts of eastern Donbas as a buffer area, saying the proposal was unfair and lacked clarity over governance, adding that Ukraine would seek alternative ways to end the conflict with Russia if the current peace talks fail.

"In my view, the most important thing is that the plan be as fair as possible," Zelensky told reporters before meeting with U.S. envoys. "The plan truly should not be just a piece of paper, but a meaningful step toward ending the war."

European leaders have voiced renewed support for Ukraine amid the diplomatic push. Last Monday, British Prime Minister Keir Starmer hosted talks in London with Zelensky, French President Emmanuel Macron and German Chancellor Friedrich Merz. The leaders agreed that the situation had reached a "critical moment" and pledged to step up support for Kiev while increasing economic pressure on Moscow.

The meeting came ahead of a planned gathering of European Union (EU) leaders later this week, where they are expected to discuss a proposal to channel billions of U.S. dollars from frozen Russian assets to Ukraine next year. Russia on Saturday warned that it would take retaliatory measures against what it calls the EU's illegal freezing of its assets.

The European show of unity followed criticism from Trump, who said he was "a little disappointed" with Zelensky and suggested Ukraine had not sufficiently engaged with U.S. peace proposals.

Trump on Tuesday criticized European leaders as "weak" and suggested the United States could scale back support for Ukraine, according to the BBC. "They talk, but they don't produce. And the war just keeps going on and on," said Trump.

Meanwhile, fighting has continued on the ground. Zelensky said on Saturday that Russia launched more than 450 drones and 30 missiles in overnight attacks, targeting energy infrastructure across several regions. Ukraine's interior ministry said the strikes left more than one million households without power.

Russian Foreign Minister Sergei Lavrov said Wednesday that Russia will respond to any deployment of European military forces in Ukraine as well as to attempts to seize Russian assets in Europe.

On Sunday, Zelensky said that he believes the United States could make Russian President Vladimir Putin accept a deal.

"If the United States truly wants to end this war ... I believe the Russians will have to make compromises," he was quoted as saying by The New York Times. Enditem