Prime Minister Boris Johnson has held talks in Kyiv with Ukraine’s President Volodymyr Zelensky.
No 10 said the visit was a “show of solidarity” with the Ukrainian people.
Following the meeting, Downing Street said the UK would send 120 armoured vehicles and anti-ship missile systems to support Ukraine.
Senior officials in Mr Zelensky’s team praised the UK for support during its conflict with Russia.
Mr Johnson’s visit to Kyiv was not announced in advance and the first indication he was in the city came when a photograph of his meeting with President Zelensky was put on Twitter by the Ukrainian embassy in London.
A Downing Street spokesman said: “The prime minister has travelled to Ukraine to meet President Zelensky in person, in a show of solidarity with the Ukrainian people.”
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In a statement after the meeting, Mr Johnson paid tribute to “President Zelensky’s resolute leadership and the invincible heroism and courage of the Ukrainian people”, saying: “Ukraine has defied the odds and pushed back Russian forces from the gates of Kyiv”.
He said: “I made clear today that the United Kingdom stands unwaveringly with them in this ongoing fight, and we are in it for the long run.
“We are stepping up our own military and economic support and convening a global alliance to bring this tragedy to an end, and ensure Ukraine survives and thrives as a free and sovereign nation.”
Read more: BBC
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