The lawyer representing President Trump in the investigation into Russia's meddling in the 2016 election also has prominent clients with connections to the Kremlin, according to a report.

Marc Kasowitz has represented Russian oligarch Oleg Deripaska, who is close to Russian President Vladimir Putin and has had business dealings with former Trump campaign manager Paul Manafort.

Kasowitz also represents Russia's largest state-owned bank, Sberbank.

The Washington Post reported Friday that Kasowitz was scheduled to represent one of Deripaska's companies in court on May 25, two days after it was reported that he had been hired by Trump. Another lawyer from Kasowitz's firm appeared in court instead.

One of Kasowitz's law partners told the Washington Post that the attorney had represented Trump more than a decade before he argued on behalf of Deripaska or Sberbank.

Congressional investigators have reached out to Deripaska's attorneys over his business interactions with Manafort. Sberbank's former vice president met with Jared Kushner, Trump's son-in-law and adviser, in December. Kushner's communications with the banker are under investigation by the FBI.

After former FBI Director James Comey's testimony to Congress on Thursday, Kasowitz publicly called for Comey to be investigated for leaking the memos he wrote about his private conversations with the president.