Russian Foreign Minister Sergei Lavrov said on Thursday Moscow would expel 60 US diplomats and close its consulate in Saint Petersburg in a tit-for-tat expulsion over the poisoning of ex-double agent Sergei Skripal.
Lavrov said the US ambassador had been informed of "retaliatory measures", saying that "they include the expulsion of the equivalent number of diplomats and our decision to withdraw permission for the functioning of the US consulate general in Saint Petersburg".
Washington earlier ordered the expulsion of 60 diplomats and shut down the Russian consulate general in Seattle.
Lavrov added that Russia would also issue tit-for-tat responses to the other countries that have expelled diplomats in a mass show of support for Britain which has blamed Moscow for the poisoning of Skripal and his daughter Yulia with a nerve agent in the city of Salisbury.
"As for the other countries it's also all symmetrical measures as to the number of people who will be leaving Russia from diplomatic missions, and that's all so far," Lavrov said.
He added that Russia was reacting to "absolutely unacceptable actions that are taken against us under very harsh pressure from the United States and Britain under the pretext of the so-called Skripal case."
He accused London of "forcing everyone to follow an anti-Russian course."
He said Britain had informed Moscow of the state of health of Yulia Skripal on Thursday and that Russia had asked again for access to her as a citizen.
Lavrov vowed at the briefing in Moscow that "we want to establish the truth" over the poisoning and accused Britain of "making mockery of international law."
He said that Russia had asked for a meeting with the executive council of the Organisation for the Prohibition of Chemical Weapons on Tuesday to ask questions to "establish the truth."
"We are counting on our Western partners not evading an honest conversation," Lavrov said.