President Donald Trump's son-in-law and senior adviser Jared Kushner was "more than willing to answer any and all questions" following reports of his meetings with Russian officials, according to a top U.S. official. CNN reported on Thursday that the Federal Bureau of Investigation was looking into Kushner's many roles on both Trump's transition team and in the White House.

The Washington Post previously reported that Sergey Kislyak, Russia's ambassador to the USA, told his superiors in Moscow that Kushner proposed a backchannel line of communication between the Trump transition team and the Russian government in December.

Reuters is reporting of at least three previously undisclosed contacts during Trump's presidential campaign between Kushner and the Russian ambassador Sergey Kislyak.

"It is my opinion that numerous leaks coming out of the White House are fabricated lies made up by the #FakeNews media", Trump tweeted.

Those changes also include, according to the anonymous sources cited by the papers, creating a "war room" to respond to the constant media reporting on the Russian Federation probe and directing the flow of the White House message on it, including the possibility that a team of attorneys may review Trump's tweets.

Fox's report claimed that the call was supposed to be a one-off communication to discuss the sitting president's approach to the Russian ally.

Trump made the comments in a statement to the New York Times on Sunday evening, a day after returning from a multicountry overseas trip.

He said the other potential problem would be if Kushner did not disclose meetings with Russian officials during the FBI's background check.

National Security Advisor H.R. McMaster refused to talk about the allegations.

Mr Kelly, the homeland security secretary, carried the same message on Sunday.

"Any way that you can communicate with people, particularly organisations that are maybe not particularly friendly to us, is a good thing".

In interviews Sunday, Kelly said he didn't know whether the reports were true.

Trump, when he returned to Washington, quickly assailed news media reports of White House turmoil linked to investigations of his aides and their ties to Russian Federation.

Mr Kushner, 36, even suggested using Russian diplomatic facilities in the United States to protect such a channel from monitoring, The Post said, quoting USA officials briefed on intelligence reports.

"You have to ask, well, who are they hiding the conversation from?" he said on ABC.

"I do think there ought to be a review of his security clearance to find out whether he was truthful, whether he was candid, " Schiff said.

While Kushner is a person of interest in that probe, it does not mean he is suspected of wrongdoing or subject to any criminal charges. White House sources told NBC News that Mr Kushner has now been advised to "lay low" while news about the FBI investigation continues to make headlines.

Mr Trump immediately sought to dismiss recent news reports as "fake news".

The unanswered questions about Russian Federation may add to declining US relations with European allies.