MOSCOW (Reuters) - BBC journalist Sarah Rainsford left Russia on Tuesday after Moscow abruptly refused to extend her permission to work in a tit-for-tat row with Britain over the treatment of foreign media.

       Russian authorities earlier this month told Rainsford, one of the British broadcaster's two English-language Moscow correspondents, to leave the country https://www.reuters.com/world/uk/russia-asks-bbc-journalist-leave-diplomatic-row-with-britain-state-tv-2021-08-13 in retaliation for what it called London's discrimination against Russian journalists working in Britain.

       Russian authorities accused London of mistreating a Russian journalist working for the state TASS news agency in London who they said was forced to leave in 2019 after his visa was not extended without explanation.

       They said they had tried and failed to get Britain to remedy the situation before deciding to retaliate in kind.

       The BBC has called the expulsion https://www.reuters.com/world/uk/bbc-says-russias-expulsion-moscow-reporter-an-assault-media-freedom-2021-08-13 of Rainsford a "direct assault on media freedom" and the British government had without success urged Russian authorities to reconsider their decision.

       Rainsford, who has said she was devastated by the move https://www.reuters.com/world/uk/bbc-reporter-says-russia-told-her-never-return-2021-08-14, posted pictures on Twitter on Tuesday from a Moscow airport before she boarded a flight out of the country.

       "I have to leave Russia," she wrote.

       Russia's foreign ministry has made clear it will not allow the BBC to send her back or replace her with someone else until Britain gives a visa to a Russian state journalist.

       (Reporting by Andrew Osborn; Editing by Tom Balmforth)