Trump shared information gathered by a U.S. partner through a sensitive intelligence-sharing arrangement, the Post reported, citing current and former U.S. officials, who said such information had not yet been shared with U.S. allies. The highly classified information included details about an Islamic State threat related to laptop computers on aircrafts, according to the Post.
Other publications, including the New York Times and Buzzfeed, confirmed the Post's account.
Members of Trump's administration quickly pushed back against the report about Trump's meeting with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergey Kislyak.
"At no time — at no time — were intelligence sources or methods discussed. And the president did not disclose any military operations that were not already publicly known," National Security Adviser H.R. McMaster said Monday night.
"I was in the room. It didn't happen," he added.
Trump has been under heavy Russia-related scrutiny amid ongoing investigations into potential links between his campaign and Russian meddling in the 2016 presidential election. The president fired FBI Director James Comey last week and later linked his decision to the FBI's Russia investigation.
"When I decided to just do it, I said to myself, I said you know, this Russia thing with Trump and Russia is a made up story," Trump said in an interview with NBC News last week.