The United States has announced more sanctions against Russia over its use of a nerve agent to try and assassinate former Russian spy Sergei Skripal in Britain in 2018, the State Department said.

The announced sanctions fall under the Chemical and Biological Weapons Control and Warfare Elimination Act and mean the U.S. will oppose loans and assistance by international financial institutions like the International Monetary Fund, and restrictions on the export on Department of Commerce-controlled goods and technology, the State Department said in a statement.

"After the first round of sanctions in response to Russia's assassination attempt against a private citizen in the United Kingdom, Russia did not provide the assurances required under U.S. law, so we are imposing the second round of sanctions," White House spokesman Hogan Gidley said in a statement Friday.

Russia has been accused of using the military-grade nerve agent Novichok to poison former double agent Sergei Skripal in March 2018. His daughter, Yulia, who was visiting him, was also sickened. They were found unconscious on a bench in the British town of Salisbury and spent weeks in critical condition but recovered.

A police officer was sickened and survived. A few months after the attack, a local man who found a perfume bottle containing traces of the nerve agent became severely ill and his girlfriend, Dawn Sturgess, died from accidental exposure.

Russia has denied any involvement. The poisoning ignited a diplomatic confrontation in which hundreds of envoys were expelled by both Russia and Western nations.

In September, British authorities charged two Russian men in absentia. Both are thought to be Russian spies.

The assassination attempt "endangered thousands of lives in Salisbury and Amesbury," a U.S. State Department spokesperson said in a statement.

Some members of Congress had recently pressed the White House to impose the sanctions as required by U.S. law over Russia's use of chemical weapons.

Reps. Eliot Engel, D-New York, and Michael McCaul, R-Texas, chairman and ranking member of the House Foreign Affairs Committee said in a joint letter late last month that the sanctions must be imposed.

They wrote that the first round of sanctions against Russia in August 2018 “largely imposed penalties that the United States had already put into place.”

"Existing law demanded this action," the two lawmakers said in a statement Friday after President Donald Trump signed an executive order laying the groundwork for the second round of sanctions.

Frants Klintsevich, a member of the Russian upper house's defense and security committee, whose views generally reflect the Kremlin's thinking, said the new sanctions would make any possibility of normalizing U.S.-Russian relations “even more hypothetical,” the Associated Press reported.

"They are the latest attack on international relations in general and on strategic stability in the world," he said.

The sanctions, which will remain in place for at least a year, are set to take effect following a 15-day Congressional notification period, or around Aug. 19, the State Department said.

Under them, the U.S. will oppose the extension of any loan or other assistance from international financial institutions like the World Bank. U.S. banks would also be barred from participating in the primary market for non-ruble bonds issued by Russia. Licenses for exports to Russia for items that could be used in chemical weapons programs would also be restricted.

The State Department said the measures "could curtail Russia's access to billions of dollars of bilateral commercial activity with the United States."