The U.S. had joined Britain in condemning Russia for the Skripal poisoning and joined with European nations in expelling Russian diplomats in response, but it had yet to make the formal determination that the Russian government had "used chemical or biological weapons in violation of global law or has used lethal chemical or biological weapons against its own nationals".
On March 4 Sergei Skripal, a former Russian spy who had worked for United Kingdom intelligence, and his daughter Yulia were found unconscious on a bench in Salisbury.
The sanctions stem from a March nerve-agent attack against a former Russian spy in the U.K. The U.S. and Britain have held Russia responsible for the attack.
The Associated Press, citing an unnamed State Department official, says that sanctions "include the presumed denial of export licenses for Russian Federation to purchase many items with national security implications".
"Once again we totally reject any allegations of possible Russian government involvement over what happened in Salisbury", Peskov said Thursday, adding that "Russia did not have and does not have anything to do with the use of chemical weapons".
The higher price of oil, however, has given Russia's government a large financial cushion to maintain public services and to assist business magnates targeted by USA sanctions.
Last month, British Prime Minister Theresa May urged Trump to raise the issue of the poisonings when he met with Russian President Vladimir Putin in Helsinki, although it remained unclear whether the subject came up in their talks.
He criticised the USA decision to link the sanctions to the British nerve agent case, an incident the Kremlin has long cast as a Western plot to damage its reputation and provide a pretext for more sanctions. One of them, Dawn Sturgess, died eight days later.
He went on to say the sanctions "contravene worldwide law".
The latest U.S. action follows the Treasury's imposition of sanctions in March against 19 Russian citizens and five entities for interfering in the 2016 United States election - the toughest steps against Moscow since Trump took office.
If Moscow violates the sanctions then it could see restrictions on flights from the Russian Aeroflot airline to the US, sanctions on USA bank loans, increased export and import restrictions, including on gas and petroleum, and potentially even a downgrade of diplomatic relations.
The sanctions are to take effect on or around 22 August, she stated. Moscow has repeatedly denied involvement. Russia's political and business leaders were quick to chalk up a summit last month between President Donald Trump and President Vladimir Putin as a victory. This included siding with the Russian leader over USA intelligence regarding alleged Kremlin interference in the 2016 elections that brought Trump to the White House.
Russia's embassy in the United States called new U.S. sanctions draconian and said the reason for the new restrictions - allegations it poisoned a former spy and his daughter in Britain - were far-fetched. Rand Paul hand-delivered a letter from Mr. Trump to Putin, asking for "expanding dialogue".