The U.S. is reportedly telling Ukraine during talks in Germany that it must withdraw troops from part of the disputed Donbas region to achieve a negotiated peace deal with Russia, according to a report.

Ukrainian and U.S. negotiators on Mondaywrapped up a second day of peace talks for the Russia-Ukraine war in Berlin on Monday, and the former are seeking further discussions, an unnamed official told Reuters.

Ukraine must agree to withdraw forces from Donetsk in the Donbas region, which is now mostly occupied by Russian, according to the anonymous official.

Ukrainian President Volodymyr Zelensky said that the issue of territorial concessions is "painful."

"Frankly speaking, we still have different positions," he said, adding that he believed U.S. mediators would help find a compromise.

Ukrainian negotiators will continue consultations with U.S. counterparts, Zelensky said, noting that his country needed a clear understanding on security guarantees, including the monitoring of a ceasefire, before making any decisions about the war's front lines.

"I do not think that the (U.S.) has demanded anything," Zelensky said. "I see us as strategic partners, so I would say that we have heard about the issue of territories in relation to Russia's vision or Russia's demands from the (U.S.) We see this as demands from the Russian Federation."

U.S. envoy Steve Witkoff and President Trump's son-in-law Jared Kushner have been participating in the talks with Zelensky and European leaders.

Rustem Umerov, Ukrainian secretary of the National Security and Defence Council, posted on X earlier on Monday, "Over the past two days, Ukrainian-US negotiations have been constructive and productive, with real progress achieved. We hope we will reach an agreement that will bring us closer to peace by the end of the day."

The deal being discussed in Berlin includes Ukraine receiving security guarantees similar to those provided in Article 5 of the NATO treaty, which requires the alliance to assist in the defense of any member that comes under attack, a U.S. official told reporters. However, security guarantees would not be on the table forever, according to U.S. officials.

Kremlin spokesman Dmitry Peskov told reporters that Russia's demand that Ukraine not join NATO was key in talks on a possible peace agreement. Peskov said Russia expects an update from the U.S. after the negotiations in Berlin.