Moscow came under pressure from the European Union today to drop its threat to shut down British Council offices in Russia region on New Year's Day.
Amid increasingly fraught relations, the UK's top diplomat told the Russian Ambassador, Yuri Fedotov, yesterday that the move would be illegal and unjustified.
The message was reinforced today by the Portuguese presidency of the EU, which urged Russia to think again.
In a statement, the presidency said cultural institutes like the British Council played a vital role in promoting understanding between countries.
It added: "In this context the European Union expresses its concern and urges the Russian authorities to revisit their decision concerning the closing down of the offices of the British Council in Yekaterinburg and St Petersburg."
Relations between Russia and Britain have hit a low following the murder in London of former KGB agent Alexander Litvinenko last year.
Moscow has steadfastly refused to extradite the man wanted by Britain in connection with the killing.
Sir Peter Ricketts, permanent secretary at the Foreign Office, yesterday repeated the UK's insistence that the British Council's presence in Russia complied with international law.
In a meeting with Mr Fedotov, he also highlighted concerns at the move within the EU.
A Foreign Office spokesman said today: "Representatives of a large number of member state cultural institutes have written to the Russian government expressing their deep concern, stressing that the British Council is fully entitled to operate in Russia, and urging the Russian Government not to carry out their threat."
He added: "The permanent secretary urged the Russian Government, through its Ambassador, to reconsider urgently its proposed action against the British Council."