President Volodymyr Zelenskiy dismissed Vadym Prystaiko as Ukraine's ambassador to Britain on Friday, days after the envoy publicly criticised the president.
A presidential order, which said Prystaiko had also been removed as Ukraine's representative to the International Maritime Organisation, gave no reason for the dismissal.
In an interview with Sky News last week, Prystaiko was asked about remarks by outgoing British Defence Secretary Ben Wallace suggesting Kyiv should show more gratitude for weapons deliveries from its allies to fight Russia's occupying forces.
Zelenskiy responded by saying Ukraine was always grateful to Britain, a staunch ally. He was also quoted by British media as saying Wallace could let him know how to express his gratitude or how "we could get up in the morning and express our words of gratitude to the minister".
Asked whether Zelenskiy was being sarcastic, Prystaiko told Sky there was "a little bit of sarcasm" when the president "said that each and every morning he will wake up and call Ben Wallace to thank him.
"I don't believe that this sarcasm is healthy," he said, adding that the Russians "have to know that we're working together".
Zelenskiy's order did not say who would replace Prystaiko, 53, an experienced diplomat and former vice prime minister who had held the post as ambassador to Britain for three years.
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