Former acting U.S. Attorney General Sally Yates told senators Monday that she warned the White House’s top lawyer that President Donald Trump’s first national security adviser, Michael Flynn, may have been “compromised” by the Russians and that the administration needed to “take action they thought was appropriate.”

In her first public remarks since being fired by Trump on Jan. 30, Yates also stood behind her decision not to defend the White House's executive order barring many Middle Eastern refugees from entering the United States.

During three hours of testimony before the Senate Judiciary Subcommittee on Crime and Terrorism, the Atlanta native said she met twice with White House counsel Donald McGahn in January to discuss the possibility of Flynn being vulnerable to blackmail by the Russians. Some news outlets have reported that the vulnerability came from Flynn discussing sanctions with Russian Ambassador Sergey Kislyak, but Yates would not confirm that.

“Logic would tell you that you don’t want the Russians to have leverage over the national security adviser,” Yates said. “We knew that was not a good situation, which is why we wanted the White House to know about it.”

Her comments contradicted past remarks from top Trump administration officials, who have described her conversation with McGahn in less serious terms.

“I would assume that when you raise your right hand and agree to tell the truth and nothing but the truth that you’ll do that. That’s the whole reason you pledge,” White House press secretary Sean Spicer reportedly told reporters Monday when asked about whether he had any reason to doubt the truthfulness of Yates’ testimony.

Yates said McGahn took her concerns “seriously” but that he expressed concern that taking action could interfere with the FBI’s investigation into Russia’s interference in the election. She said she did not know how McGahn and others proceeded after she relayed the information since she was fired soon thereafter. (Flynn ultimately wasn’t fired for two more weeks, only after news of Yates’ conversations with the White House was reported by the press.)

Yates said she also raised concerns about Vice President Mike Pence unknowingly being misled by Flynn, who had served as the head of the Defense Intelligence Agency under President Barack Obama.

At several points during her Senate testimony, Yates said she could not talk about details of the government’s investigation into Russia or Flynn’s conduct since she was not allowed to discuss information that was classified or under investigation. That included who in the intelligence community ordered that Flynn’s name be revealed in government reports that featured interceptions from foreign diplomats’ communications.

Republican senators pressed Yates and James Clapper, the former director of national intelligence under Obama, about how classified information was leaked to the media in the first place, a point Trump made on Twitter earlier Monday.

“Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Counsel,” he tweeted Monday morning.

Both Yates and Clapper said they were not responsible for the leaks, nor did they authorize anyone to share the classified information with the press.

Refugee executive order

When questioned about the executive order on refugees, two versions of which have since been halted in court, Yates said she believed she was upholding the Constitution by refusing to defend the action, even though the Justice Department’s Office of Legal Counsel determined it was legal.

Yates said the Office of Legal Counsel looks purely “at the face of the document” but that it didn’t take into account other factors, including the Constitution’s establishment, equal protection and due process clauses.

“I don’t believe that there are reasonable legal arguments that are grounded in truth that can be made in defense of this argument that the travel ban was not intended to have a religious impact to disfavor Muslims,” she said.

“In this particular instance … it was appropriate for us to look at the intent behind the president’s action,” she added.

U.S. Sen. Ted Cruz, R-Texas, suggested that Yates’ action to not defend the executive action was partisan and that it broke with long-standing precedent.

“There’s no doubt the arguments you’ve laid out are arguments that we could expect from partisan litigants (in court) who disagreed with the policies and the president,” he said.

Yates’ blockbuster testimony came as the White House struggled to put nonstop questions about Russian meddling in the election in the rearview mirror amid several congressional inquiries and an FBI probe.

After the hearing, Trump tweeted: “Director Clapper reiterated what everybody, including the fake media already knows — there is ‘no evidence’ of collusion w/ Russia and Trump.”

In the hours before the hearing, NBC News reported that Obama had warned Trump not to hire Flynn when he met with the then-president-elect in November and that Flynn had not disclosed $34,000 in payments from a Russian state media outlet when he renewed his security clearance last year.

Yates had initially been scheduled to testify before the House Intelligence Committee last month, but that hearing was canceled by the panel’s chairman after a reported legal dispute between Yates’ lawyer and the White House about whether she was barred from testifying due to “executive privilege.”

Democratic operatives have floated Yates' name as a potential candidate for governor or other statewide office in 2018, but Yates has so far stayed silent on the issue.

The 56-year-old has deep roots in Georgia. She graduated from the University of Georgia School of Law and worked at the King & Spalding law firm in Atlanta before becoming an assistant U.S. attorney in Atlanta in 1989. Her father had served as a judge on the Georgia Court of Appeals.

She was promoted to U.S. attorney for the district in 2010 before Obama tapped her for the No. 2 job at the Justice Department in 2014. She was confirmed by the U.S. Senate months later with overwhelming bipartisan support, including the backing of Republican U.S. Sens. Johnny Isakson and David Perdue.