London (CNN) Twenty-three Russian diplomats have left the UK for Moscow less than a week after being expelled over the poisoning of a former spy in Britain.

Around 80 people, including the diplomats' families, flew out of Stansted Airport near London on Tuesday to the Russian capital.

Reuters video showed a small crowd gathered outside the Russian embassy, hugging and waving goodbye to others boarding vehicles with diplomatic plates. They were later filmed boarding a Russian Air Force plane, bid farewell by Russian Ambassador to the United Kingdom Alexander Yakovenko.

"Unfortunately it is very sad that the British government decided to behave like that, to treat us like that," Yakovenko said from the tarmac, adding that it was a "violation of international law."

People say goodbye outside the Russian Embassy in London on Tuesday.

Russia and the UK have been embroiled in a bitter diplomatic row since Russian former double agent Sergei Skripal, 66, and his daughter, 33-year-old Yulia Skripal, were poisoned in the English cathedral city of Salisbury on March 4.

People wave to others aboard diplomatic vehicles leaving the Russian Embassy.

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