Jared Kushner sits in Vice President-elect Mike Pence's car outside of Trump Tower, December 7, 2016 in New York City.

Special Counsel Robert Mueller is investigating the business and financial dealings of White House aide and U.S. President Donald Trump's son-in-law Jared Kushner, the Washington Post reported on Thursday, citing officials familiar with the matter, who spoke on condition of anonymity because they were not authorized to speak publicly.

The probe into Kushner's business dealings is part of the special counsel's investigation into Russia's interference in the 2016 presidential election.

While the Washington Post previously reported Kushner's contacts with Russian ambassador Sergey Kislyak and Sergey Gorkov, the head of a state-owned Russian development bank, were being examined, the report noted it wasn't clear at the time that the FBI was scrutinizing Kushner's business deals.

The report said Peter Carr, a spokesman for Mueller, declined to comment on the scope of the investigation, but noted that the Special Counsel's Office would deal "severely" with anyone making unauthorized disclosures.

"We do not know what this report refers to. It would be standard practice for the Special Counsel to examine financial records to look for anything related to Russia," Jamie Gorelick, a lawyer for Kushner, said in a statement received by CNBC. "Mr. Kushner previously volunteered to share with Congress what he knows about Russia-related matters. He will do the same if he is contacted in connection with any other inquiry."

The White House and the Department of Justice did not immediately respond to CNBC's emailed requests for comment, where were sent outside of office hours.

For the Washington Post story, please click here.

Watch: Kushner will cooperate with investigation, says Spicer