Special counsel probe charging Flynn with one count of 'willfully and knowingly' making false statements
Court documents posted online show the investigation being led by Special Counsel Robert Mueller is charging Flynn with one count of "willfully and knowingly" making false statements about his contacts with Russia's former U.S. envoy, Sergey Kislyak, during the transition in American administrations.
Should Flynn enter the guilty plea as expected, it would be the most significant indication to date that he is cooperating with Mueller's investigation.
Mueller is probing allegations Russia sought to interfere in last year's presidential race through what U.S. intelligence agencies have termed an "influence campaign", and whether the Trump campaign cooperated with the effort.
Trump has staunchly denied any cooperation took place.
Flynn left the administration in disgrace in February shortly after assuming his senior post amid disclosures he lied to officials, including Vice President Mike Pence, about his contacts with Kislyak.
He is the fourth person charged in Mueller's investigation.