The disclosure included information that could jeopardize “a critical source of intelligence on the Islamic State,” including the source's location and other identifying details, The Post reported.
McMaster also attended the meeting. A photographer working for Russian state-owned media was allowed to photograph the meeting, but no American news agencies were given access.
>> Related: WaPost: Trump revealed classified information to Russia during recent meeting
“In the context of that discussion, what the president discussed with the foreign minister is ... wholly appropriate,” McMaster said Tuesday, adding that Trump and Lavrov were discussing the threat of terrorism. “He’d also raised some difficult issues ... (and) then the president was emphasizing ‘Hey, we have some common interests here.”
McMaster added that while Trump’s disclosure didn’t jeopardize national security, the story being leaked to news agencies did.
“Our national security has been put at risk by those violating confidentiality,” McMaster said, again emphasizing that Trump did not disclose confidential information. “I think it’s important to investigate these sorts of things.”
>> Related: Trump responds to reports that he revealed classified info to Russia
The comments are similar to ones made by McMaster after The Post reported Monday about the meeting. Several other news agencies, including The New York Times and Reuters, also confirmed the reports, citing unidentified sources.
“The president and the foreign minister reviewed common threats from terrorist organizations to include threats to aviation,” McMaster told The Post. “At no time were any intelligence sources or methods discussed, and no military operations were disclosed that were not already known publicly.”
He reiterated his comments while addressing reporters at the White House later Monday.
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"At no time were intelligence sources or methods discussed and the president did not disclose any military operations that weren't already publicly known," McMaster told reporters Monday, according to CNN. "I was in the room. It didn't happen."
Trump took to Twitter on Tuesday morning to address the controversy, writing that he had “the absolute right” to share “facts pertaining to terrorism and airline flight safety.”
“Plus, I want Russia to greatly step up their fight against ISIS and terrorism,” he wrote.