Britain is expelling 23 Russian diplomats in response to an attack on a former double agent in southern England.
Prime Minister Theresa May announced the punishment to U.K.'s Parliament on Wednesday, calling the attack a "barbaric act."
May said the diplomats were identified as "undeclared intelligence officers" and that they have one week to leave the U.K.
Russia has denied any connection to the nerve agent used to poison Sergei Skripal and his daughter March 4 at a mall in Salisbury, England. The two are still in critical condition.
May said earlier this week it is "highly likely" Russia was behind the attack. She told Parliament the nerve agent was military grade and likely made in Russia.