The expulsion order, announced by administration officials, also closes the Russian consulate in Seattle. The Russians and their families have seven days to leave the United States, according to officials.
The expulsions are the toughest action taken against the Kremlin by President Trump, who has been criticized for not being firm enough with President Vladimir V. Putin of Russia. The officials said the action was a coordinated effort with other allies. Poland on Monday announced it will expel the Russian ambassador and several other diplomats in response to the poisoning.
In a call with reporters, senior White House officials said that the move was to root out Russians actively engaging in intelligence operations against the country, and to show that the United States would stand with NATO allies. The officials said that the closure of the consulate in Seattle was ordered because of its proximity to a U.S. naval base.
"Today’s actions make the United States safer by reducing Russia’s ability to spy on Americans and to conduct covert operations that threaten America’s national security," the White House said in a statement.
The Kremlin has maintained that it had nothing to do with the poisoning.
Britain previously expelled 23 Russian diplomats over the poisoning, raising tensions between the two countries to a level not seen since the heights of the Cold War. The government vowed to crack down on Russian spies, corrupt elites and ill-gotten wealth in Britain.
Mr. Trump has been slower to act than leaders in Britain, France and Germany over the attack, in which Sergei V. Skripal, 66, a former spy, and his daughter, Yulia Skripal, 33, were attacked with a nerve agent.
The senior administration officials who described the expulsion order said the three weeks that lapsed between the attack and White House action was due to close coordination among about a dozen American allies.
Poland positioned itself to take a lead role in coordinating a response from the Eastern European nations traditionally most wary of their giant neighbor to the east.
The Russian ambassador to Poland, Sergei Andreyev, was summoned to the foreign ministry on Monday morning and informed of imminent diplomatic action against his country. The Polish foreign minister was expected to make an announcement later this afternoon.
Any expulsion of Russian diplomats would be an unprecedented move on Warsaw’s part, the first time they took diplomatic action against their neighbor due to Russian behavior outside of Poland.
Since Poland broke from the Soviet bloc in the 1990s, it has expelled Russian diplomats only twice — and both times to had to do with Russia’s spying activities in Poland.