Caught in the middle of an escalating diplomatic row between Russia and the UK, the British Council has temporarily closed its St Petersburg offices.
The director of the centre to promote cultural ties said they had to shut because all the members of staff were being questioned by police.
On Monday, Moscow refused to issue new visas to British Council employees after the organisation defied an order not to reopen in January.
British Foreign Secretary David Miliband said: “Any intimidation or harassment of officials is obviously completely unacceptable.
“The only losers from any attack on the British Council are the Russian citizens who want to use the British Council – 1.25m last year – and the reputation of the Russian government.”
Furious at the re-opening of the offices after the New Year break, Russian Foreign Minister Sergei Lavrov has accused Britain of breaking Russian law.
He said: “I understand, of course, that historical memory, maybe linked to nostalgia for the colonial era, sometimes prevails over the legal aspect of the matter. But, in any case, one cannot speak to Russia in this way.”
Relations between Russia and the UK have been strained since the death of former KGB agent Alexander Litvinenko.
When Russia refused to extradite the man UK investigators suspect of poisoning him, Britain expelled four Russian officials, triggering a series of tit-for-tat measures.