The US is to impose sanctions on Russia after determining that it used nerve agent against former Russian double agent Sergei Skripal in the UK in March.
The move was announced on Wednesday by the US state department.
A UK investigation blamed Russia for the attack, but the Kremlin has strongly denied any involvement.
Mr Skripal and his daughter Yulia were found unconscious on a bench in the city of Salisbury on 4 March.
They were seriously ill but recovered after spending several weeks in hospital.
The US determined “that the government of the Russian Federation has used chemical or biological weapons in violation of international law, or has used lethal chemical or biological weapons against its own nationals”, US state department spokeswoman Heather Nauert said.
BBC reports that the sanctions are to take effect on or around 22 August, she added.