Jared Kushner, US President Donald Trump's son-in-law and close adviser, made a pre-inauguration proposal to the Russian envoy to set up a secret and bug-proof communications line with Moscow, according to a Washington Post report.

The report is the latest allegation of potential collusion between Trump's campaign team and Russia, which US government intelligence agencies have accused of meddling in last year's election in the Republican's favour.

Kushner proposed using Russian diplomatic facilities in the United States for the secure communications, the Post reported late on Friday, citing anonymous US officials briefed on intelligence reports.



The alleged proposal was made at a meeting on December 1 or 2 at Trump Tower in New York with Russia's Ambassador Sergei Kislyak, weeks before Trump took office.

Kislyak, whose communications with his superiors about the meeting were intercepted by the US, "reportedly was taken aback by the suggestion", according to the Post.

Kushner, 36, is a real estate developer who is married to Trump's daughter, Ivanka. He is a trusted behind-the-scenes adviser to Trump, involved in everything from Middle East peace to an initiative to streamline the US bureaucracy.

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The December meeting was also attended by Michael Flynn, Trump's former national security adviser, who resigned after just 25 days on the job and who is at the centre of the FBI's Russia probe into whether there was any collusion between the Trump campaign and the Kremlin.

Kushner also met that month with Sergei Gorkov, chairman of VneshEconomBank, the Russian state-owned bank under US sanctions since July 2014.

Both those meetings have since been publicly acknowledged by the White House, but Kushner initially failed to declare them on forms submitted to obtain a security clearance.



His lawyer later said it was a mistake, telling the FBI that he would amend the forms.

The White House did not immediately comment on the Post's Friday report.

'Witch hunt'

Besides the Kushner developments, which strikes at Trump's core by drawing his family into the crisis, the White House also faces a cascade of other worries in the coming week.

James Comey, the fired ex-FBI director, has promised to testify at a yet unscheduled open session before the Senate Intelligence Committee, sometime after Monday's Memorial Day holiday.



And the White House staff itself could be facing upheaval. CBS News reported that Trump is expected to consider plans for a shakeup of his communications operation upon his return.

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The FBI investigation is now being overseen by Robert Mueller, a respected former FBI director who was given broad powers to pursue the case as a special counsel after Trump abruptly fired Comey on May 9.

Trump has denied any collusion between his campaign and Russia, calling the probe "the greatest witch hunt" in American political history.

Russia has also denied interfering in the November 8 US election.



Former CIA director John Brennan revealed this week that intelligence chiefs had been looking into suspicious contacts between Trump campaign associates and Russian officials since mid-2016.

"It should be clear to everyone Russia brazenly interfered in our 2016 presidential election process and that they undertook these activities despite our strong protests and explicit warning that they do not do so," he told the US House of Representatives Intelligence Committee.

The Senate and House Intelligence Committees also are investigating, but not with an eye to bringing criminal charges.