President Donald Trump took to Twitter on Tuesday morning to defend his sharing of what is reportedly highly classified information with Russian officials — a story that has exploded overnight.

The Washington Post reported Monday that Trump divulged the information during a meeting with last week with Russian officials including Foreign Minister Sergey Lavrov.

Current and former intelligence officials told the Post that the president disclosed highly classified information pertaining to the Islamic State.

BuzzFeed, The New York Times and Reuters later confirmed the Post's report, while White House officials denied it, saying Trump didn't discuss intelligence sources or methods of collection.

H.R. McMaster, Trump's national security advisor, told reporters Monday that "The story that came out tonight, as reported, is false."

"At no time were intelligence sources or methods discussed," said McMaster, who didn't take questions. "I was in the room, and it didn't happen."

Trump tweeted that he shared the intelligence with the Russians because of "humanitarian reasons" and said he wants Russia to "greatly step up" its fight against ISIS.

@realDonaldTrump: 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....

@realDonaldTrump: ...to terrorism and airline flight safety. Humanitarian reasons, plus I want Russia to greatly step up their fight against ISIS & terrorism.

@realDonaldTrump: I have been asking Director Comey & others, from the beginning of my administration, to find the LEAKERS in the intelligence community.....

Russia's Foreign Ministry has rebuked claims that Trump divulged highly classified information to Russian officials during a visit to the Oval Office, calling them "harmful" and "dangerous."

— CNBC's Karen Gilchrist and NBC News contributed to this report.