Prime Minister Boris Johnson has held talks in Kyiv with Ukraine's President Volodymyr Zelensky, Downing Street has said.
The visit was a "show of solidarity" with the Ukrainian people.
A spokesman said Mr Johnson was using the trip to set out a new package of financial and military aid.
The spokesman said: "The prime minister has travelled to Ukraine to meet President Zelensky in person, in a show of solidarity with the Ukrainian people".