Special counsel Robert Mueller is probing the business dealings of Jared Kushner, President Donald Trumps son-in-law and adviser, as part of the investigation into Russias interference in the 2016 presidential election, the media reported.
The Washington Post had previously reported that investigators were scrutinising meetings that Kushner held with Russians in December, first with Russian Ambassador Sergey Kislyak, and then with Sergey Gorkov, the head of a state-owned Russian development bank.
At the time of that report, it was not clear that the Federal Bureau of Investigation (FBI) was investigating Kushner's business dealings.
However, Mueller's investigation is in a relatively early phase, and it is unclear whether criminal charges will be brought when it is complete, US officials familiar with the matter told The Washington Post on Thursday.
The development comes a day after the daily reported that Mueller had extended his probe into determining whether the President tried to obstruct justice by suggesting to top intelligence and law enforcement officials that they end the Russia investigation.
"We do not know what this report refers to," Jamie Gorelick, an attorney for Kushner, said in response.
"It would be standard practice for the Special Counsel to examine financial records to look for anything related to Russia. 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."
Kushner has agreed to discuss his Russian contacts with the Senate Intelligence Committee, which is conducting one of several investigations into Russian meddling in the 2016 election.
During the December meeting with Kislyak, Kushner suggested establishing a secure communications line between Trump officials and the Kremlin at a Russian diplomatic facility, reports The Washington Post.
The Russian bank, Vnesheconombank, which has been the subject of US sanctions following Russia's annexation of Crimea, has said Gorkov and Kushner's meeting was held for business reasons because of the advisor's role as head of his family's real estate company.
The meeting occurred as Kushner's company was seeking financing for its troubled $1.8 billion purchase of an office building in New York.