President Trump's personal attorney composed a tweet that implied Mr. Trump knew his former national security adviser Michael Flynn had lied to the FBI when he demanded his resignation in February, sources with direct knowledge of the situation tell CBS News.

On Saturday, a tweet from Mr. Trump's account stated that he "had to fire General Flynn because he lied to the Vice President and the FBI." John Dowd was the principal wordsmith for the tweet, and it's unclear whether Mr. Trump saw the final version, sources said. The president was in between fundraisers in New York when the tweet was sent from an iPhone.

Sources acknowledged Mr. Trump's tweet was unhelpful, raising questions about what the president knew and when.

I had to fire General Flynn because he lied to the Vice President and the FBI. He has pled guilty to those lies. It is a shame because his actions during the transition were lawful. There was nothing to hide! — Donald J. Trump (@realDonaldTrump) December 2, 2017

Dowd meant to convey that Flynn was fired for lying to Pence and other White House officials about his conversations with Kislyak, and "now we know" that he lied to the FBI, according to these sources. But Dowd bungled the tweet and created confusion around Mr. Trump's knowledge of events.

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Flynn pleaded guilty to one count of lying to the FBI on Friday, becoming the first current or former White House official to face charges in Special Counsel Robert Mueller's investigation into Russian meddling in the 2016 election.

The Washington Post first reported Dowd's authorship of the tweet.

Mr. Trump fired Flynn on Feb. 13, 2017, nearly two weeks after then-Acting Attorney General Sally Yates warned White House Counsel Don McGahn that Flynn had misled Vice President Mike Pence about his contacts with Sergey Kislyak, the Russian ambassador to the U.S.

Mr. Trump's apparent admission on Saturday that he knew Flynn lied to the FBI -- a federal crime -- was seen by many as evidence of obstruction of justice. The day after Flynn's resignation, Mr. Trump urged then-FBI Director James Comey to "let this go," referring to the FBI's investigation into Flynn's ties to foreign contacts. Comey was fired just weeks later. Mueller's team is investigating whether Comey's firing constituted obstruction of justice.

Earlier Saturday, Mr. Trump told reporters that there was "no collusion, no collusion" with Russia.

"There's been absolutely no collusion, so we're very happy," he said from the White House South Lawn before departing for New York.

Jacqueline Alemany contributed to this report.