Ushakov said Russia has not yet seen the proposals, but will not accept changes that contradict its repeatedly stated position.

"If there are corresponding amendments, we will have very sharp objections," Ushakov said, adding that Moscow clearly laid out its position, which "was fully understandable to the Americans."

He called the prospect of Ukraine becoming a NATO member "impossible."

Ukrainian President Volodymyr Zelensky on Sunday indicated his willingness to drop the goal of Ukraine joining NATO in exchange for security guarantees from the West. “That is already a compromise on our part,” he said, adding that the security guarantees must be legally binding.

Ukraine's official policy has long been to pursue NATO membership, a goal which was enshrined in its Constitution in 2019. Zelensky’s offer to give up NATO aspirations meets one of Russia's demands, but Kyiv says it remains steadfast in its position on other issues.

Talks between US and Ukrainian delegations on resolving the Russia-Ukraine conflict continued in Berlin on Sunday. Specific proposals have not yet been made public.

German Chancellor Friedrich Merz is scheduled to meet President Zelensky in Berlin on Monday.