Russia announced on Thursday the expulsion of 60 US diplomats and the closure of the American consulate in St. Petersburg in retaliation for Washington’s decision to boot an equal number of Russian diplomats over the poisoning of double-agent Sergei Skripal.

“Based on the reciprocity principle, as a retaliatory measure, 58 employees of the US Embassy in Moscow and two staff members of the Consulate-General in Yekaterinburg have been declared personae non gratae for the activities incompatible with their diplomatic status,” Russia’s foreign ministry said.

The expelled diplomats have until April 5 to leave Russian soil, while personnel at the US Consulate-General in St. Petersburg must abandon the premises no later than Saturday, Efe reported.

“US Ambassador to Russia Jon Huntsman has been summoned to our ministry, where my deputy Sergei Ryabkov is briefing him on the tit-for-tat steps against the US,” Russian Foreign Minister Sergei Lavrov said Thursday at a press conference in Moscow.

Russia’s action came three days after Washington ordered the expulsion of 60 Russian diplomats – including 12 working at the United Nations – and the closure of the Russian Consulate in Seattle.

The United States is among more than two-dozen countries that have ordered upwards of 150 Russian diplomats to leave as a gesture in support of the United Kingdom, which accuses Moscow of being behind the poisoning of Skripal and his daughter, Yulia.

On March 4, the Skripals were found unconscious on a park bench in Salisbury, England, where 66-year-old Sergei settled after being released from a Russian prison in a spy swap.

Both father and daughter remain hospitalized, but doctors said Thursday that Yulia, 33, is “improving rapidly and is no longer in a critical condition. Her condition is now stable.”

The British government said the Skripals were poisoned using a nerve agent of “a type developed by Russia.”

Moscow denies any responsibility for the poisoning and Lavrov on Thursday accused Washington and London of “encouraging a slanderous campaign against our country.”

Russia plans to carry out proportionate expulsions of diplomats from every country that has ordered Russian diplomats to get out, Lavrov said.