A former ally of New Jersey Governor Chris Christie is expected to plead guilty on Friday to criminal charges related to the George Washington Bridge closure scandal, according to several news reports.

David Wildstein, who had been a senior Christie appointee to the Port Authority of New York and New Jersey, is expected to plead guilty in the first charges stemming from the September 2013 incident, which created four days of traffic snarls on the Hudson River crossing into New York City, the New York Times and Wall Street Journal reported.

The precise nature of the charges was not clear. Bloomberg News reported on Wednesday that charges were expected against Wildstein.

U.S. Attorney for New Jersey Paul Fishman announced early on Friday there would be a "proceeding of interest in a criminal matter" at 11 a.m. (1500 GMT) in U.S. district court in Newark. Fishman then will hold a press conference at 1 p.m. ET (1700 GMT) at his office.

Wildstein's attorney, Alan Zegas, could not immediately be reached for comment.

In December, a New Jersey legislative panel blamed Wildstein and another Christie aide for ordering the bridge lanes closed.

Christie has denied knowing about the incident, and the joint panel of Democrats and Republicans in December found no evidence he was involved. The political fallout has hurt his brand as he considers a run for the Republican presidential nomination.