The Trump administration’s decision to impose further sanctions against Russia following the poisoning of former Russian spy Sergei Skripal and his daughter in the UK earlier this year is “categorically unacceptable” and “illegal,” according to President Vladimir Putin’s spokesman Dmitry Peskov.

The US State Department announced Wednesday that sanctions would be imposed under a chemical and biological warfare law and would go into effect around August 22.

The statement also accused Russia of violating international law.

During a regular press call on Thursday, Peskov said that it was “too early” at the moment for possible retaliatory sanctions to be discussed and reiterated the claim that Russia was not involved in the poisoning of the former spy in Salisbury, England.

Skripal 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 released in May.

The UK and its allies have blamed Russia for the attack.