NBC reporter Richard Engel tweeted Monday that the classified information President Trump discussed with top Russian officials in the Oval Office "wasn't anything they didn't already know," citing a U.S. intelligence official.

The Washington Post reported Monday that, during a meeting last week with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergey Kislyak, "Trump went off script and began describing details of an Islamic State terrorist threat related to the use of laptop computers on aircraft."

The Post wrote that Trump's disclosures "jeopardized a critical source of intelligence" on ISIS, and an official told the newspaper that he had revealed "code-word information" that was "more information to the Russian ambassador than we have shared with our own allies."

Engel, however, wrote that an intelligence official told him it was Trump attempting to show the Russians "how cooperative he wants to be with them" in the fight against ISIS and it was "not new info."

Us intel official tells me trump told russians about laptop airline threat. Told it wasnt anything they didnt already know. @washingtonpost — Richard Engel (@RichardEngel) May 16, 2017

Us intell official says trump was trying to show russians "how cooperative he wants to be with them" in fight against isis. @washingtonpost — Richard Engel (@RichardEngel) May 16, 2017

National Security Adviser H.R. McMaster said Monday night that the Post story was "false."

"At no time were intelligence sources or methods discussed, and the president did not disclose any military operations that were not already publicly known," he said.

Trump tweeted on Tuesday, however, that he was within his rights to "to share with Russia … facts pertaining to terrorism and airline flight safety."

As President I wanted to share with Russia (at an openly scheduled W.H. meeting) which I have the absolute right to do, facts pertaining…. — Donald J. Trump (@realDonaldTrump) May 16, 2017