U.S. ambassador's critical tweet about American democracy

The U.S. Ambassador to Qatar has tweeted an atypically critical statement about developments back home.

Dana Shell Smith tweeted early Wednesday that it is "Increasingly difficult to wake up overseas to news from home, knowing I will spend today explaining our democracy and institutions."

Smith didn't elaborate as to what news she was referring to. Her tweet came a few hours after President Donald Trump abruptly fired FBI Director James Comey amid an ongoing FBI investigation into Russian ties with members of Trump's campaign.

Trump is the first president since Richard Nixon to fire a law enforcement official overseeing an investigation with ties to the White House.

Smith, a career diplomat, was confirmed as ambassador to Qatar in July 2014.