Trump's tweet raises obstruction specter, worries allies

Shifting explanations for why President Donald Trump fired National Security Adviser Michael Flynn are renewing questions over whether Trump may have obstructed an ongoing investigation of potential contacts between his campaign and Russia.

Pressure on the administration has mounted since Flynn last week pleaded guilty to lying to the FBI about reaching out to the Russians on the president's behalf.

The muddled response from the White House has alarmed several of Trump's closest confidants, who have grown increasingly worried that Trump is not being well-served by his legal team.

The president's aides and legal advisers have scrambled for 48 hours to explain a Saturday tweet, which suggested Trump knew Flynn lied to the FBI when he fired him.

The White House has since said Trump did not write the tweet.