US President-elect Donald Trump's incoming Ukraine envoy will travel to Kyiv and several other European capitals in early January as the next administration tries to bring a swift end to the Russia-Ukraine war, according to two sources with knowledge of the trip's planning, Reuters reports.

Retired Lieutenant General Keith Kellogg, who is set to serve as Trump's special envoy for Ukraine and Russia, is not planning to visit Moscow during this trip, said the sources.

Instead, he will visit senior leaders in Kyiv, and his team is working to set up meetings with leaders in other European capitals, such as Rome and Paris, said the sources.

The meetings are expected to focus on fact-finding on behalf of the incoming Trump administration, rather than on active negotiations, the sources said.