The UK will expel 23 Russian diplomats in retaliation for a nerve agent attack on a former Russian double agent on British soil.
That's according to British Prime Minister Theresa May, who said the diplomats have been identified as "undeclared intelligence officers".
(SOUNDBITE) (English) BRITISH PRIME MINISTER THERESA MAY, SAYING:
"They have just one week to leave. This will be the single biggest expulsion for over 30 years and it reflects the fact that this is not the first time that the Russian state has acted against our country. Through these expulsions, we will fundamentally degrade Russian intelligence capability in the UK for years to come."
High-level bilateral communications with Moscow will also be suspended, she said.
One impact of that will be no British minister or members of the royal family at the World Cup in Russia later this year.
Russian state assets will also be frozen, May said, if there is evidence that they may be used to harm "the life or property of UK nationals or residents."
The measures are a response to the poisoning of Sergei Skripal and his daughter Yulia.
They were found unconscious on a bench in the quiet English city of Salisbury on March 4, and remain in a critical condition.
The British government has identified the substance used as Novichok, a nerve agent developed by the Russian military in the 1970s and 80s.
Moscow was given until the end of Tuesday (March 13) to explain how Novichok came to be used in the attack.
Russia said it would not respond to that ultimatum until the UK sent it samples of the nerve agent.
"They have treated the use of a military grade nerve agent in Europe with sarcasm, contempt and defiance."
Russia has dismissed all suggestions that it is responsible and called British accusations "a political performance".
Moscow said London should expect a retaliation for its actions.