Russia has summoned a slew of senior Western diplomats to tell them how many of their embassy officials it was expelling in a worsening stand-off with the West over the poisoning of a former Russian spy and his daughter in Britain.
Moscow said on Thursday it was expelling 60 US diplomats and would eject scores from other countries that had joined London and Washington in censuring Moscow over the poisoning of Sergei Skripal and his daughter Yulia.
Britain and Russia have already expelled 23 of each other's diplomats over the first known use of a military-grade nerve agent on European soil since World War II, but Laurie Bristow, Britain's ambassador, was summoned again on Friday.
The Russian foreign ministry said in a statement Bristow had been told London had just one month to cut its diplomatic contingent in Russia to the same size as the Russian mission in Britain.
It was not immediately clear if that meant a serious cut in staff numbers. A spokeswoman for the British Foreign Office said Russia's response was regrettable and that Moscow was in flagrant breach of international law over the killing of the former spy.
The poisoning, in southern England, has united much of the West in taking action against what it regards as the hostile policies of President Vladimir Putin.
Russia rejects Britain's accusation it stood behind the attack and has cast the allegations as part of an elaborate Western plot to sabotage East-West relations and isolate Moscow.
The Russian foreign ministry said in a statement on Friday it was summoning the representatives of a "raft of countries", including Australia, that had taken what it called unfriendly action against Russia in solidarity with Britain because of the Skripal affair.
"The envoys will be handed protest notes and told about the Russian side's retaliatory measures," the ministry said.
Embassy officials from Australia, France, Germany, Italy, Poland, the Netherlands, Croatia, Belgium, Ukraine, Sweden, Canada and the Czech Republic were all seen arriving in their official cars at the foreign ministry building in Moscow.
The US and a range of Western countries are expelling around 130 Russian diplomats and Moscow has said its own measures will precisely mirror those actions.
Emerging from the Russian Foreign Ministry building, German ambassador Rudiger von Fritsch said Russia had questions to answer about the poisoning of Mr Skripal, but that Berlin remained open to dialogue with Moscow.
The US State Department said after Russia announced the expulsions on Thursday evening, that it reserved the right to respond further, saying the list of diplomats designated for expulsion by Russia showed Moscow was not interested in diplomacy. Kremlin spokesman Dmitry Peskov, in a conference call with reporters on Friday, disagreed with that assessment, saying that Putin still favoured mending ties with other countries, including with the US.