Russia on Saturday ordered 23 United Kingdom diplomats to leave the country within a week, Reuters reported. The order follows the United Kingdom’s expulsion of 23 Russian diplomats after Moscow refused to meet British Prime Minister Theresa May’s March 13 ultimatum to provide information about the nerve agent attack on a former double agent.

The United Kingdom has accused Russia of being responsible for the attack and the British foreign secretary said Russia President Vladimir Putin may have given the order for the March 4 attack.

Moscow also announced the closure of the British Council in Russia and its decision to withdraw the permission granted to the United Kingdom to open a general consulate in St Petersburg. Russia’s foreign ministry released a statement about the developments after a meeting with Britain’s ambassador to Russia, Laurie Bristow.

Later on Saturday, May said her government “will never tolerate a threat to the life of British citizens”. She made the statement during a party conference, The Independent reported.

On March 15, the United Kingdom, the United States, France and Germany had declared Russia responsible for the attack in a joint statement. The North Atlantic Treaty Organisation and the European Union also expressed their solidarity with the United Kingdom.

Russia’s Foreign Minister Sergei Lavrov had rejected claims about Russia’s role in the attack. Lavrov had said Russia’s requests to see the samples of the nerve agent had been turned down which, he claimed, violated the chemical weapons convention that outlaws the production, stockpiling, and use of chemical weapons. He said under the convention, Moscow has 10 days to reply to an official accusation.

The attack

Former spy Sergei Skripal and his daughter Yulia were found unconscious on a bench outside the Maltings shopping centre in Salisbury on March 4. Both of them, and a police officer who first responded to them, are said to be in serious condition in hospital. Police said the substance that rendered them critically ill was a nerve agent