Washington (CNN) The Trump administration will impose more sanctions on Russia under a chemical and biological warfare law following the poisoning of a former Russian agent and his daughter in the UK earlier this year, the State Department announced Wednesday.

In a statement Wednesday, State Department spokeswoman Heather Nauert said the US had made this decision on Monday, and accused Russia of violating international law. The statement anticipated the sanctions would go into effect around Aug. 22 in line with the Chemical and Biological Weapons Control and Warfare Elimination Act of 1991.

Sergei Skripal, a former Russian spy, and his daughter Yulia Skripal were hospitalized and treated for a nerve-agent attack in March. Yulia Skripal was discharged from the hospital in April, and her father was discharged in May.

The State Department notified Congress on Wednesday of the first of two potential tranches of sanctions required under the 1991 law. Unless Russia takes certain steps, a second set of penalties -- more stringent than this first round -- must follow, according to the law.

The first set of sanctions targets certain items the US exports to Russia that could have military uses -- so-called dual use technologies. These are sensitive goods that normally would go through a case-by-case review before they are exported. With these sanctions, the exports will be presumptively denied.

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