Jared Kushner is being scrutinised by the FBI as part of the investigation into possible ties between the President’s election campaign and Russia.
The Washington Post says the investigation centres around meetings Mr Kushner had with the Russian ambassador Sergei Kislyak and Moscow banker Sergei Gorkov.
Mr Gorkov is the chairman of VneshEconomBank – a state bank which has been under US sanctions since 2014.
In a statement provided to Sky News, Mr Kushner’s attorney Jamie Gorelick said: “Mr Kushner previously volunteered to share with Congress what he knows about these meetings. He will do the same if he is contacted in connection with any other inquiry.”
The husband of Mr Trump’s daughter Ivanka, as well as Mr Trump’s senior aide, Mr Kushner is the only current White House official understood to be involved in the probe.
While he is being questioned as part of the inquiry, there has been no suggestion that he is a target of the investigation itself, and he has not been accused of any wrongdoing.
Former Trump campaign manager Paul Manafort and sacked national security adviser Michael Flynn are both considered to be subjects of the probe.
The investigation is being led by ex-FBI chief Robert Mueller, following the abrupt sacking of former FBI director James Comey.
Mr Trump has been accompanied by Mr Kushner and his daughter Ivanka during his first foreign presidential trip.
Before heading off on the week-long tour, the President suggested he was being unfairly treated in the Russia investigation, claiming that he was thevictim of the “greatest witch hunt” in US political history.