President Trump called former FBI Director James Comey “crazy” and “a real nut job” in a meeting with Russia’s foreign minister earlier this month in order to explain why the U.S. has been unable to cooperate with the Kremlin, national security adviser H.R. McMaster claimed Sunday.

“The gist of the conversation was that the president feels as if he is hamstrung in his ability to work with Russia to find areas of cooperation because this has been obviously so much in the news,” McMaster said in an interview with ABC News’ George Stephanopoulos.

Trump met with Russian foreign minister Sergey Lavrov and ambassador Sergey Kislyak in the Oval Office on May 10, the day after he fired Comey. (RELATED: Trump Told Russians He Fired ‘Nut Job’ Comey)

“I just fired the head of the FBI. He was crazy, a real nut job,” Trump said, according to a readout of notes provided to The New York Times.

“I faced great pressure because of Russia. That’s taken off,” Trump continued.

“I’m not under investigation.”

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McMaster told Stephanapoulos that he did not recall exactly what Trump said in the meeting. He also said he was unaware that Trump would raise Comey’s firings with the Russian officials.

The report Friday sent the White House scrambling to come up with a defense for Trump’s remarks. Some observers said that Trump’s comment is evidence of potential obstruction of justice in the ongoing investigation into potential collusion between the Trump campaign and Kremlin.

Writing at the conservative National Review, former federal prosecutor Andrew McCarthy called Comey a “patriot” and Trump’s remarks “indefensible.”

“There is no excuse for a president of the United States to run down an American for the consumption of our Russian adversaries — particularly an American who is fighting against Russia’s operations against our country,” wrote McCarthy, a conservative who has been critical of the sprawling investigation of potential collusion between the Trump team and Russia.

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