Fired acting Attorney General Sally Yates said in an interview Tuesday that "there was nothing casual" about warnings she gave the Trump administration about then-national security adviser Michael Flynn.

In an interview with CNN's Anderson Cooper, Yates disputed White House press secretary Sean Spicer's characterization of her warnings that Flynn could be open to blackmail by Russia as a "heads up."

"I absolutely did not use the term 'heads up.' "There was nothing casual about this," Yates said.

"I called [White House councel] Don McGahn and told him I had a very sensitive matter that I needed to discuss with him that day and it needed to be in person," Yates said. She added: "And Mr. McGahn got it. He knew that this was serious and that it was important."

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President Donald Trump in an interview with NBC News’ Lester Holt last week said McGahn met him after the meeting with Yates and it didn't sound like the Flynn issue was an emergency.

"When you call the White House counsel and say you have got to meet with them that day about something you can't talk about on the phone, and you tell them that their national security adviser may be able to be blackmailed by the Russians, and that you're giving them this information so that they'll take action, I'm not sure how much more of a siren you have to sound,"

Flynn resigned on Feb. 13 and acknowledged he gave incomplete information to Vice President Mike Pence about phone calls with Russian ambassador Sergey Kislyak, which occurred before Trump was inaugurated. Trump has said "I fired him because of what he said to Mike Pence."

Yates said in the interview that she didn’t recommend that Flynn be fired in her meeting with McGahn — I told him it wasn't our call," she said — but added that "there's certainly a criminal statute that was implicated by his conduct."

Trump fired Yates on Jan. 30 after she directed Justice Department lawyers not to defend the Trump administration’s executive order on immigration. That order and a revised order that attempted to address legal concerns have since been blocked by courts.

Yates’ CNN interview was her first on television since she was fired. The interview was taped on Monday, before the news about a memo by fired FBI Director James Comey documenting a request by Trump for Comey to drop his probe into Flynn.

Yates said she was informed of her firing by a letter that arrived at her office. After directing the Justice Department to not defend the executive order she said she knew dismissal was a possibility, but that it still was a "punch in the gut" when the letter arrived.

"But to have done anything else I felt like would have been an abdication of my responsibility," Yates said. "So I wasn't looking to be fired. But given the situation that I was in, I couldn't have done anything else and lived with myself."