Former acting Attorney General Sally Yates warned the White House that former national security advisor Michael Flynn "essentially could be blackmailed" by Russia more than two weeks before he was fired, she said Monday.
Yates made her first public comments on the events as she and former Director of National Intelligence James Clapper testified before a subcommittee of the Senate Judiciary Committee during a hearing on alleged Russian interference in the 2016 election. President Donald Trump removed Flynn in February after it was revealed that he had lied about the nature of his conversations with Sergey Kislyak, the Russian ambassador to the United States.
Russian elements had the ability to blackmail Flynn because they knew — and likely had proof — that he had lied about the nature of the conversations they had with the national security advisor, Yates said. That created what she called a "compromise situation."
"To state the obvious, you don't want your national security advisor compromised with the Russians," Yates told the Senate panel.
The Trump administration has faced questions about why it hired Flynn to the key post, particularly after it came to light that the Pentagon is investigating Flynn over whether he got permission to accept payments from foreign governments, including a 2015 speaking engagement in Moscow. It also has faced criticism about the amount of time that elapsed between Yates' warning and when Flynn got fired.
Yates said she warned the White House on Jan. 26 that Flynn, a retired Army lieutenant general, could be vulnerable. The former acting attorney general spoke to White House counsel Donald McGahn in person twice and once over the phone, she said.
"We were giving them this information so that they could take action," Yates said. She stressed that she did not believe Vice President Mike Pence, who relayed Flynn's incorrect version of events in the press, knowingly misled the public.
Yates added that McGahn asked at the time why the Department of Justice would care if one White House official misled another. She said "it was a whole lot more than one White House official lying to another," adding that Flynn's "underlying conduct," not just his statements to Pence, was "problematic."
McGahn also asked whether the White House should fire Flynn, but Yates did not give a recommendation, she said.
Trump attempted to get ahead of the testimony in Monday morning tweets. He noted that Flynn's security clearance was renewed under the Obama administration, adding that "the Fake News seldom likes talking about that."
Trump is correct that Flynn's clearance was renewed under Obama, but Flynn was removed from his defense intelligence post by the Obama administration in 2014. Critics have asked why the Trump administration didn't catch possible problems with Flynn during its own vetting process.
Obama warned Trump against hiring Flynn shortly after the November presidential election, NBC News reported. White House spokesman Sean Spicer argued Monday that the Obama administration could have taken steps to suspend Flynn's security clearance if the administration was "really concerned."
Obama "made it known that he wasn't exactly a fan of Gen. Flynn's," Spicer said.
In his tweets Monday, Trump also took the unusual step of suggesting a topic that he hopes senators will address with Yates in the hearing. He said she should be questioned about "how classified information got into the newspapers soon after she explained it to W.H. Counsel."
Asked if Trump suggested that Yates had a role in releasing classified information, a claim that no evidence currently supports, Spicer said Trump's tweet "speaks for itself." Both Yates and Clapper said they did not know how the details about Flynn's conversations made it to The Washington Post, which first reported that he may have misled Pence about his conversations with Kislyak.
The hearing comes amid congressional probes into Russia's influence on the election and possible ties between the Trump campaign and Russia. The FBI is conducting a separate counterintelligence investigation.
Clapper repeated Monday that he did not personally know of any collusion between the Trump campaign and Moscow, though he noted that he did not know of the FBI investigation until the bureau's director, James Comey, revealed it in March.
Yates declined to say if she knew of any collusion, one of several topics she declined to go into, saying she did not want to reveal classified information. However, she stressed that people should not read into that as an indication that collusion took place.
Later Monday, Trump tweeted in response to Clapper and Yates testimony.
Flynn was a Trump campaign advisor before he was made part of the administration. His conversations with the Russian ambassador took place after Trump's election but before his inauguration, a period during which the incumbent administration has traditionally handled foreign policy.
Trump repeatedly has denied that his campaign colluded with Russia, and has even cast doubt on whether the Kremlin tried to influence the election at all. Moscow claims it did not try to meddle, though the Kremlin is widely believed to have interfered in the elections of multiple Western nations, including Sunday's vote in France.
Trump fired Yates in late January after she told Justice Department lawyers not to defend Trump's first executive order restricting travel from seven Muslim-majority countries. That came before current Attorney General Jeff Sessions was confirmed by the Senate.
— CNBC's Ted Kemp contributed to this report