The report in the Post could not immediately be independently confirmed and goes beyond reporting in other outlets. It stems from an anonymous letter the paper received in mid-December. Intelligence officials, the paper said, subsequently confirmed Kushner’s desire to establish a secret channel so that the Trump team could conduct politically sensitive communications.

National-security officials expressed surprise at Kushner’s reported move, which would circumvent the federal government’s established methods for communicating with foreign powers, including Russia.

"Why would Kushner want a secret channel? What information would the Trump team want to make sure is hidden from U.S. intelligence?" asked Clint Watts, a former FBI agent and a fellow at the Foreign Policy Research Institute. "The idea of using Russian facilities to skirt Russian surveillance in the U.S. would either be a serious attempt to hide something or the actions of a young amateur."

Ali Soufan, a former FBI agent who now runs the Soufan Group security firm, echoed that assessment.

“I'm trying to think of one really good reason for them to do something like this, and I seriously can't come up with any,” said Soufan of Kushner’s attempt to use Russian facilities to correspond with the Kremlin. "It indicates a lack of experience, at the least.”

In April, the New York Times reported that Kushner failed to disclose meetings with Russian officials. Kushner’s attorney Jamie Gorelick, a former Clinton-era Justice Department official with extensive national security experience, said the omission was an error and that the questionnaire had been submitted “prematurely.”

Shortly after the Post’s story was published on Friday, Reuters reported Kushner also had two previously unknown phone calls with Kislyak. One of the calls reportedly took place in April as Trump neared the end of the Republican primary season; the other occurred sometime in November. The report did not specify whether the second call took place before or after the November 8 election, nor did it indicate whether Kushner or Kislyak initiated the calls.

Kushner returned to Washington this week part way through Trump’s first foreign trip, although White House officials insisted his early departure had been planned. He was greeted by reports from multiple outlets, including NBC News and the Post, that he is now a focus of the FBI’s investigation into the possibility of collusion between the Trump campaign and Russia. It’s part of a broadening set of inquiries facing Trump. Separately on Friday, the Post reported that the Senate Intelligence Committee had asked the Trump campaign to preserve and produce all documents, emails, and phone records dating back to its inception in June of 2015.

The Trump inner circle’s clandestine communications with Kislyak before the inauguration have dogged the administration for months. The president fired Flynn in February after multiple news outlets reported he had lied to White House officials, including Vice President Mike Pence, about conversations he had with the Russian ambassador in December. Those conversations took place on the same day the Obama administration imposed sanctions on Russian officials for interfering in the 2016 presidential election.