UPDATE (WKOW) -- Michael Flynn has pleaded guilty to one count of lying to the FBI.
He appeared in court in Washington, D.C. at 10:30 Eastern Time.
Sources tell ABC News Flynn is cooperating fully with Mueller's investigation and this plea deal signals he may testify against senior Trump officials and possibly President Donald Trump himself.
People close to Flynn told ABC News the general felt President Trump abandoned him and has agreed to answer questions about the president or anyone else.
UPDATE (WKOW) -- Michael Flynn is accused of "willfully and knowingly" making false statements to the FBI while serving in the Trump administration.
Court documents released Friday show Flynn is charged with a single count of making false statements. Prosecutors with Special Counsel Robert Mueller's office say Flynn falsely stated to the FBI he had not discussed sanctions with the then-Russian ambassador to the U.S.
Flynn is the fourth person charged in connection with Mueller's investigation. Former Trump campaign chairman Paul Manafort and his deputy Rick Gates were indicted last month. They have both pleaded not guilty. Trump campaign foreign police adviser George Papadopoulos pleaded guilty to making a false statement to the FBI over contacts with officials connected to the Russian government.
WASHINGTON, D.C. (WKOW) -- Former national security adviser Michael Flynn is being charged with making false statements to the FBI.
He has a plea hearing at 10:30 a.m. ET, where ABC News reports he's expected to plead guilty.
Flynn was under investigation by Special Counsel Robert Mueller and his team as part of the investigation into Russia's election meddling.