The sanctions were imposed under the provisions of the Chemical and Biological Weapons Control and Warfare Elimination Act of 1991, which mandates that once the government has determined that a country has used chemical or biological weapons in violation of global law or even made "substantial preparations" to do so, sanctions must be imposed.
While both Skripals survived the attack, the US sided with Britain in determining Russian Federation was responsible after investigators concluded the would-be assassins used a Soviet-era nerve toxin known as "Novichok".
With those possible exemptions in mind, the State Department estimated the value of the new sanctions could "reach potentially hundreds of millions of dollars". -Russian relations. A 1991 law, however, mandates sanctions once the president makes a determination that a country is responsible for a chemical or biological weapons attack.
Instead, he said there were also delays in triggering the same type of USA sanctions after the two most recent chemical or biological attacks, one in Sryia by the Assad regime and another perpetrated by North Korea.
In April 2018, the Trump administration imposed sanctions on seven of Russia's richest men-or "oligarchs"-as well as 17 top government officials, to put pressure on President Vladimir Putin's inner circle".
Mr Putin, himself a former KGB spy, said earlier this month Mr Skripal would have been dead if he was attacked with a weapons-grade agent. One of them, Dawn Sturgess, died eight days later.
The US sanctions came despite President Donald Trump's efforts to improve relations with Russia and its leader, Vladimir Putin, and his harsh criticism of the investigation into Russian interference in the 2016 election.
The new USA sanctions will stop Russian state-owned firms from buying certain American electoronic devices.
Although the U.S. says it is sanctioning Moscow over the Sergei Skripal case, the measures are actually due to internal USA politics which have led to a "sanctions war" in Washington, writer and journalist Neil Clark told RT.
The sanctions are to take effect on or around 22 August, she stated.
But Peskov said the sanctions undo the goodwill curried by presidents Trump and Putin at their Helsinki summit last month.
State Department officials said there would be "carve-outs" in the sanctions for "the provision of foreign assistance to Russia and to the Russian people", as well as for joint spaceflight activities and commercial aviation.
A terse release from the State Department said that the United States had determined Russian responsibility for the attack in Salisbury, England - a British conclusion the administration had already accepted - under a 1991 USA law on biological and chemical weapons use that requires the president to impose sanctions.
The sanctions came as an eagerly-watched contest for a previously safe Republican seat in the USA congress went to the wire, leading to speculation that voters were turning against Donald Trump and could punish the Republican Party at mid-term elections.
"In our view, these and earlier restrictions are absolutely unlawful and don't conform to global law", Mr Peskov said.