Kushner spoke with Sergey Kislyak, the Russian ambassador to the USA, about creating the secret line to make it easier to hold sensitive discussions about the conflict in Syria, according to a person familiar with the discussions.
Russia, a pivotal player in Syria, has backed Syrian President Bashar al-Assad, often at the expense of civilians during a long civil war. The White House declined to comment. At the time, a White House official dismissed it as a brief courtesy meeting.
The White House did not acknowledge the meeting or Mr. Kushner's attendance until March.
The newspaper cited anonymous USA officials who were briefed on intelligence reports on intercepted Russian communications.
The report says Kushner wanted the back channel to avoid monitoring of their communications, and that Kislyak was "taken back" by the suggestion that included the possibility of arranging a meeting in a third country. Tillerson was sworn in on February 1. "It says an very bad lot about us as a society that we could actually harbor those kinds of feelings that the organs of the state would be used by my predecessor to come after me or to intercept my communications or to disrupt my administration in a way that made it seem legitimate to me to use the secure communications facilities of a foreign power".
"The idea that the Federal Bureau of Investigation director's decision to jump into the election and say that Hillary Clinton did not commit a crime but [that] she was pretty much incompetent was based on a fake e-mail from Russian Federation", he added "is a stunning story". But they did not dismiss the idea that the administration would go outside normal US government and diplomatic channels for communications with other countries.
Asked whether he would be concerned as a general matter if someone in the administration or National Security Council sought backchannel communications with the Russian embassy, McMaster said he would not.
Such a back channel would be unprecedented, said retired four-star Gen. Michael Hayden, who also once headed the National Security Agency.
Cohn said: "We're not going to comment on Jared".
Kushner was a trusted Trump adviser previous year, overseeing the campaign's digital strategy, and remains an influential confidant within the White House as does his wife, Ivanka Trump.
The FBI, in the course of its investigation into Russian involvement in the 2016 election, is now also looking at Kushner's multiple roles in Trump's campaign operation and his contacts with Russian officials. The person, like others, spoke on condition of anonymity in order to discuss private conversations. Kushner's lawyer said he will co-operate with investigators.
The Post first reported the request, which covers materials such as emails, phone records and documents dating to Trump's first days as a candidate in July 2015. Kushner is eager to cooperate with any and all inquiries, this official said.
Backchanneling is a practice at times used by government officials, but Kushner was not yet a government employee at the time of his contact with Russian Ambassador Sergey Kislyak in December. Kushner's attorney, Jamie Gorelick, told Reuters that Kushner "has no recollection of the calls as described".
Recently appointed special counsel Robert Mueller, a former FBI director, is starting off an investigation with a broad mandate that will allow him to probe both the possible Russian influence and whether Trump attempted to obstruct the investigation by firing FBI Director James Comey.
Current and former American officials said Kushner's activities, like those of many others around Trump, are under scrutiny as part of the investigation.
"Really, being spoken to, does not confer a target status on the individual", he said. Kushner "suggested using Russian diplomatic facilities in the United States for the communications", the Post reported, in an apparent attempt to try to shield discussions during the transition from monitoring. "He will do the same if he is contacted in connection with any other inquiry".