A top Ukrainian official has begun a visit to the United States to build contacts with the incoming administration of President-elect Donald Trump, who has promised to end Russia's war in Ukraine upon taking office, Ukrainian media cited the country's foreign minister as saying on Wednesday.

Ukraine's presidential chief of staff Andriy Yermak was already in the U.S., Foreign Minister Andriy Sybiha told reporters in Brussels, news agency Interfax Ukraine reported.

"This contact at the level of the head of the (president's) office is very important for establishing, among other things, relations with representatives of the new administration,” Sybiha was quoted as saying by Interfax Ukraine.

Trump has thus far avoided giving details about his plans to stop the 33-month invasion, but three plans put forward by people close to him all see Kyiv's long-coveted NATO membership prospects taken off the table.

Trump's advisors have also floated proposals that would see large territorial concessions made to Moscow, which occupies one-sixth of Ukraine.