The United States says it has imposed sanctions on a Ukrainian lawmaker behind leaked telephone records of Democratic presidential hopeful Joe Biden, as well as three other “Russia-linked” individuals accused of attempting to influence the U.S. electoral process.

The U.S. Treasury Department said in a statement on September 10 that it had blacklisted Andriy Derkach, who has been helping President Donald Trump’s personal lawyer Rudy Giuliani find compromising information on Mr. Biden.