By David Jones

NEWARK, New Jersey (Reuters) - A key aide to New Jersey Governor Chris Christie testified on Friday in a far-reaching criminal investigation into the September 2013 lane closures near the George Washington Bridge, media reported.

Michael Drewniak, a longtime spokesman for the embattled moderate Republican, a possible contender for the White House in 2016, spoke for about two hours before 23 members of a federal grand jury at a U.S. courthouse in Newark, ABC News reported.

It did not report specifics on what Drewniak said, though he is not a target of the investigation.

Christie was widely considered a leading contender for the Republican presidential nomination in 2016 after winning reelection in heavily Democratic New Jersey last year.

But a scandal saw several key Christie aides implicated in apparently manufacturing a traffic jam. It has hurt his standing in U.S. polls and among some Republicans.

State lawmakers and federal prosecutors are separately investigating the lane closures leading to the bridge that links New Jersey and New York City.

U.S. Attorney Paul Fishman launched an investigation in January to determine whether any federal laws had been broken.

A spokesperson for Fishman declined to comment on the ongoing investigation.

Attorney Anthony Iacullo, who represents Drewniak in the investigation, could not be immediately reached for comment.

Several key figures in the Christie administration and the Port Authority of New York and New Jersey have either resigned or been terminated amid a probe by New Jersey legislators.

A report released last month by a law firm hired by Christie to investigate the lane closures concluded Bridget Anne Kelly, the governor's former deputy chief of staff, and David Wildstein, a Christie appointee to the Port Authority of New York and New Jersey, were the key players who orchestrated the massive traffic jam.

(Reporting by David Jones in Newark, New Jersey; Editing Eric M. Johnson)