The United States is imposing tough new sanctions on Russia after determining Moscow was responsible for poisoning a former Russian spy and his daughter in Britain in March.

The State Department says Russia broke international law when it used a lethal nerve agent against its own nationals.

A policeman found Sergei Skripal and his daughter Yulia slumped over on a bench and unconscious in the British city of Salisbury. It was determined that they were sickened by Novichok – a Soviet-era military-grade nerve agent. Both survived but spent weeks in the hospital.

 

WATCH: US Imposes New Sanctions on Russia for Poisoning Former Russian Spy in Britain

The sanctions announced Wednesday are set to take effect on August 22. They generally affect U.S. licenses for exporting sensitive national security goods to Russia, such as electronics.

A senior State Department official said Wednesday that Russia could face another round of “more Draconian” sanctions within 90 days unless it provides “reliable assurances” it is no longer using chemical or biological weapons.  

Despite President Donald Trump’s mantra that “no one has been tougher on Russia” than his administration, the sanctions announced Wednesday are mandatory. They were triggered by a 1991 Congressional law, the Chemical and Biological Weapons Control and Warfare Elimination Act.

The British Foreign Office says it welcomes the U.S. sanctions.

“The strong international response to the use of a chemical weapon on the streets of Salisbury sends an unequivocal message to Russia that its provocative, reckless behavior will not go unchallenged,” it said in a statement.

Russia has not reacted so far to the sanctions. But it has denied any involvement in the Skripal poisonings.

It also said it had nothing to do with the poisoning of a British couple near Salisbury in June who picked up a bottle that also contained Novichok, killing 44-year-old Dawn Sturgess. Her boyfriend, Charlie Rowley, survived.

British officials have told reporters they have identified at least two suspects in the Skripal attack. Newspaper reports say the two are in Russia, and Britain is getting ready to ask for their extradition.