Russia on Friday ordered the United States to cut hundreds of diplomatic staff in retaliation for a new round of US sanctions, and said it was seizing two US diplomatic properties.
Moscow's decision, which had echoes of the Cold War, was announced by the Foreign Ministry a day after the US Senate overwhelmingly approved new sanctions on Russia. The legislation was in part a response to conclusions by US intelligence agencies that Russia meddled in the 2016 US presidential election, and to further punish Russia for its annexation of Crimea in 2014.
The bill goes to President Donald Trump, who could give it final approval or veto it.
Russia had been threatening retaliation for weeks. Its response suggests it has set aside initial hopes of better ties with Washington under Trump, something the US leader, before he was elected, had said he wanted to achieve.
Relations were already languishing at a post-Cold War low because of the allegations that Russian cyber interference in the election was intended to boost Trump's chances, something Moscow flatly denies. Trump has denied any collusion between his campaign and Russian officials.
The Russian Foreign Ministry complained of growing anti-Russian feeling in the United States, accusing "well-known circles" of seeking "open confrontation".
President Vladimir Putin had warned on Thursday that Russia would have to retaliate against what he called boorish US behavior. Putin's spokesman, Dmitry Peskov, told reporters on Friday that the Senate vote was the last straw.
The ministry said the United States had until Sept. 1 to reduce its diplomatic staff in Russia to 455 people, the number of Russian diplomats left in the United States after Washington expelled 35 Russians in December.
It was not immediately clear how many US diplomats and other workers would be forced to leave either the country or their posts, but the Interfax news agency cited an informed source as saying "hundreds" of people would be affected.
A diplomatic source told Reuters that it would be for the United States to decide which posts to cut, whether occupied by US or Russian nationals.