US President Barack Obama on Thursday expelled 35 Russian diplomats and ordered sanctions on Russian intelligence services over what the US government says was Moscow-ordered interference in the US presidential election.
Obama said his actions were in response to the Russian government's "cyber operations aimed at the US election," adding that "all Americans should be alarmed by Russia’s actions."
The sanctions target nine entities and individuals, including two Russian intelligence services and three companies that provided material support to one of the intelligence services, Obama said in a statement.
In addition the State Department is declaring "persona non grata" 35 Russian intelligence operatives, meaning they must leave the country within 72 hours.
It is additionally shutting down two Russian compounds in the United States used by Russian personnel for intelligence-related purposes.
The Russian government rejected the allegations.
"As we have already said before, we believe such decisions, such sanctions to be groundless and illegal from the point of view of international law," Kremlin spokesman Dmitry Peskov said in a statement carried by Tass.
Peskov added that the sanctions are "regretfully a display of unpredictable and, arguably, aggressive foreign policy" and are intended to deal a blow to both Russian-US relations and the future administration’s foreign policy.
Obama had promised to respond to Russian hacking after the US intelligence community said in October that the Russian government had intentionally interfered with the US presidential election process by directing attacks on email systems used by US political organizations.
The breaches included a hack of Democratic Party emails in July that exposed favouritism toward Hillary Clinton over rival Bernie Sanders.
US officials believe the hackers stole emails that were later released by WikiLeaks. Emails hacked from the account of John Podesta, the chairman of Clinton's campaign, were also made public.
President-elect Donald Trump, who has vowed to seek better relations with Russian President Vladimir Putin, said he would meet next week with the leaders of the US intelligence community to be updated on the facts of the situation.
Trump has cast doubt on the US intelligence agencies' conclusion over Russian involvement in the hacks and has suggested that the United States should not retaliate against Russia.
His statement on Thursday also said, "It's time for our country to move on to bigger and better things."
Because Obama's steps are executive actions, Trump could theoretically reverse them once he is in office "but it wouldn't make a lot of sense," a senior Obama administration official said in a background briefing.
The official added that because the Russian interference also threatened US economic and business interests, it should be of "concern to future administrations."
A report will be issued at a later date laying out more details on the cyber-attacks, but officials said that given the onerous task of setting up a sanctions regime, the evidence to justify it must be able to stand up in court.
House Speaker Paul Ryan praised Obama's move, saying it "is overdue," but the Republican's statement also criticized the administration for "eight years of failed policy with Russia."
Obama stood by the US claim that the data theft and disclosure activities could only have been directed by "the highest levels of the Russian government."
He also said the sanctions followed repeated private and public warnings to the Russian government, calling them a "necessary and appropriate response to efforts to harm US interests in violation of established international norms of behaviour."
The sanctions target Russia's largest foreign intelligence agency, including four individual officers of the agency, and its state security organisation.
Obama also ordered the secretary of the treasury to designate two Russian individuals for using cyber-enabled means to cause misappropriation of funds and personal identifying information.
In addition, the Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI) also will release declassified technical information on Russian intelligence service cyber activity with the goal of helping network administrators defend against Russia's "global campaign of malicious cyber activities."
The DHS and FBI issued a joint statement saying the activity by Russian intelligence services is part of a "decade-long campaign of cyber-enabled operations directed at the US government and its citizens."
It said the campaigns targeted government organizations, critical infrastructure, think tanks, universities, political organizations and corporations and included the release of stolen information.
The US government also will report to Congress in the coming days about Russia's efforts to interfere in the US election, Obama said. Congress has vowed to conduct hearings into Russia’s role in the election.