Russian Federation has warned new U.S. sanctions against Moscow approved by the House of Representatives will take already battered ties to a new low, and said it was close to taking retaliatory measures of its own.
It was not immediately clear how many USA diplomats and other workers would be forced to leave the country.
That warning reflected rising frustration in Moscow over the Trump administration's refusal to hand back two Russian diplomatic compounds which were seized at the same time as the diplomats were sent home.
The Russian Foreign Ministry said the United States had until September 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.
In a statement on Friday, Russia's foreign ministry said: "The US is stubbornly taking one crudely anti-Russian step after another, using the utterly fictitious pretext of Russian interference in its internal affairs".
The legislation all but dashes Trump's hopes for warmer ties with Moscow as his administration is dogged by congressional and special counsel investigations into Russian meddling in the 2016 USA presidential election to sway it in Trump's favour.
Trump repeatedly pledged during his campaign to try to boost relations with Russian Federation, but allegations that the Kremlin meddled in the vote to get him to the White House have made any signs of going soft on Moscow politically toxic.
The Russian Foreign Ministry said on Friday that the United States had time until September, 1 to reduce its diplomatic staff in Russia to 455 people, the same number of Russian diplomats it said were left in the U.S. after Washington expelled 35 Russians in December.
"We reserve the right in a manner of reciprocity to other measures that may affect the interests of the United States", the ministry said in a statement. But the bill is expected to garner enough support in both chambers to override any veto.
The House of Representatives and the Senate have voted for another round of sanctions against Russian Federation this week.
"The new bill seeks to create unfair competitive advantages for the United States in the global economy via political tools", the ministry said.
Russia will give a "mirror response" should the United States introduce new unilateral measures to cut the numbers of Russian diplomats in the country.
The bill would affect a range of Russian industries and might further hurt the Russian economy, already weakened by 2014 sanctions imposed after Russia annexed Crime from Ukraine.
The text is also directed at Iran and North Korea, aims to punish Moscow for its putative interference in the american presidential election past year, in respect of which an investigation is underway in the United States.
Relations between Russian Federation and the United States dropped to a post-Cold War low following Russia's annexation of Crimea and interference in eastern Ukraine in 2014. We believed and we continue to believe that global issues could only be resolved jointly.
"Despite Washington's constant attacks, we acted and continue acting responsibly and reservedly and have not responded to certain provocations until now". "The latest events show that in well-known circles in the United States, Russophobia and a course toward open confrontation with our country have taken hold".