National Security Adviser Michael Flynn sits before U.S. President Donald Trump and Japanese Prime Minister Shinzo Abe hold a joint press conference at the White House on February 10, 2017 in Washington, DC.

Story highlights

Members of Trump's transition team alerted Flynn in November that any conversations with Kislayk were most likely being monitored

Former acting Attorney General Sally Yates is expected to testify before a Senate Judiciary subcommittee Monday about her warnings to the White House on Flynn

Washington CNN  — 

Donald Trump’s transition team warned former national security adviser Michael Flynn about the risks of communicating with Russian Ambassador Sergey Kislyak, a former US official has confirmed to CNN.

Members of Trump’s transition team alerted Flynn in November that any conversations with Kislayk were most likely being monitored, a warning that took place weeks before the two discussed US sanctions on Russia by phone, according to The Washington Post, which first reported the development.

The head of Trump’s national security transition team, Marshall Billingslea, requested Obama administration officials provide a classified CIA profile on Kislyak to show to Flynn out of concern that he didn’t completely appreciate the Russian ambassador’s motives, a source close to Billingslea confirmed to CNN.

Billingslea, a former Pentagon official under George W. Bush, knew at the time that the retired Army lieutenant general would talk with Kislyak soon, the source said.

Several former Trump transition officials expressed doubt about the assertion that the transition team warned Flynn about talking to the Russian ambassador.

“Sounds like a bit of revisionist history to me,” one of those officials said. “I bet everyone interviewed by the FBI (said) they warned against the Russians.”

The development comes as former acting Attorney General Sally Yates prepares to testify before a Senate Judiciary subcommittee Monday that she gave a forceful warning to the White House that Flynn had not been truthful in public and private statements denying that he and Kislyak discussed sanctions on Russia, according to sources familiar with her account.

White House press secretary Sean Spicer told reporters in mid-February, however, that Yates had simply “wanted to give a ‘heads-up’ to us on some comments that may have seemed in conflict with what he (Flynn) had sent the vice president.”

In her warning, Yates told the administration that Flynn’s conversations with Kislyak and his subsequent statements denying he spoke about the sanctions could make him vulnerable to blackmail by Russian officials, the sources said.

Flynn was forced to step down as national security adviser just weeks after President Donald Trump took office after reports surfaced that Flynn misled the administration about his conversations with the Russian ambassador.

“I inadvertently briefed the Vice President-Elect and others with incomplete information regarding my phone calls with the Russian Ambassador,” Flynn wrote in February, according to a copy of his resignation letter obtained by CNN. “I have sincerely apologized to the President and the Vice President, and they have accepted my apology.”

CNN’s Jeff Zeleny, Jim Sciutto, Manu Raju and Pamela Brown contributed to this report.