United States President Barack Obama has announced a series of sanctions against Russian individuals and agencies in response to what he called an effort to undermine the US presidential election.
35 Russian officials are also being expelled, and two Russian compounds in the US are being closed for what Obama said was an unprecedented level of harassment against US diplomats.
US intelligence agencies have stated that they are confident Russian hackers played a role in manipulating the outcome of the November's election, which saw a Republican sweep of the White House and Congress.
Obama also echoed their assertion that the Kremlin ordered the hacking.
The Kremlin has vowed retaliation, and said these sanctions are unlawful and destroy diplomatic relations between the two countries.
TRT World's Malcolm Brown is in Washington DC with more on the US response.