Reporters follow Michael Flynn outside the US Federal Court in Washington, DC on December 1, 2017. 
Donald Trump's former top advisor Michael Flynn pleaded guilty Friday to lying over his contacts with Russia, in a dramatic escalation of the FBI's probe into possible collusion between the Trump campaign and Moscow. The fourth, and most senior, figure indicted so far in the investigation into Russian interference in last year's election, Flynn appeared in federal court in Washington for a plea hearing less than two hours after the charges against him were made public.Ex-Trump aide Flynn says he recognizes his actions 'were wrong'. / AFP PHOTO / mari matsuri        (Photo credit should read MARI MATSURI/AFP/Getty Images)