Amid persistent rumors of Ukrainian withdrawal from the war’s most prolonged battle, officials said nothing about the size or purpose of the reinforcement.
The U.S. secretary of state’s diplomatic mission is part of a broader Biden administration effort to strengthen support for Ukraine, or at least push neutral nations to refrain from aiding Russia.
A three-week fight in the town of Vuhledar in southern Ukraine produced what Ukrainian officials say was the biggest tank battle of the war so far, and a stinging setback for the Russians.
President Aleksandr G. Lukashenko’s visit comes shortly after the United States accused Beijing of preparing to give arms and ammunition to Russia to help its war on Ukraine.