Russia has decided to expel 23 British diplomats who must leave Moscow within a week, its foreign ministry said on Saturday, after summoning Britains ambassador to Russia. In retaliation for British Prime Minister Theresa Mays decision to kick out 23 Russians, Moscow has also decided to close the British Council in Russia and to withdraw permission for Britain to open a general consulate in St. Petersburg, the ministry said in a statement. It said the move was a response to Britains "provocative actions" and "baseless accusations over the incident in Salisbury on March 4," referring to the poisoning of former Russian spy Sergei Skripal and his daughter Yulia with a nerve agent developed in the Soviet Union, which Britain has blamed on Russia. The ministry also warned Britain that "if further unfriendly actions are taken towards Russia, the Russian side retains the right to take other answering measures." The war of words between Moscow and London over the attack on Skripal, 66, and Yulia, 33, escalated on Friday as Britains Foreign Secretary Boris Johnson said his governments "quarrel" was with President Vladimir Putin rather than the Russian people. "We think it overwhelmingly likely that it was his decision to direct the use of a nerve agent on the streets of the UK, on the streets of Europe, for the first time since the Second World War," Johnson said. Putins spokesman Dmitry Peskov responded saying Johnsons claims violated all rules of diplomatic protocol. Linking Putin to the attack on Skripal, who moved to Britain in a 2010 spy swap, "is nothing but shocking and unforgivable behavior from the point of view of diplomacy", Peskov said. In a rare joint statement, the leaders of Britain, France, Germany and the United States on Thursday condemned the attack as an "assault on UK sovereignty". The former spy had taken his daughter, who was on a visit from Moscow, out for lunch before they both collapsed on a bench in Salisbury. They are both in a critical but stable condition in hospital.