TRENTON, N.J. » Gov. Chris Christie today apologized to his constituents and said he was "embarrassed and humiliated" by his staff but had no idea his aides may have closed highway lanes to exact political retribution.

Christie also said he was firing Deputy Chief of Staff Bridget Anne Kelly, "because she lied to me."

Kelly is the latest casualty in a widening scandal that threatens to upend Christie’s second term and likely run for president in 2016. Documents show she arranged traffic jams to punish the mayor, who didn’t endorse Christie for re-election.

The revelations thrust a regional transportation issue into a national conversation raising new questions about the ambitious governor’s leadership on the eve of a second term designed to jumpstart his road to the White House.

The U.S. attorney in New Jersey, Paul Fishman, said he was "reviewing the matter to determine whether a federal law was implicated."

The messages do not directly implicate Christie, but they contradicted his assertions that the closings were not punitive and that his staff was not involved.

Christie acknowledged today that was a lie, because his staff didn’t tell him what they had done.

He also said he had "no knowledge or involvement in this issue, in its planning or execution" and was stunned by the "abject stupidity that was shown." Nevertheless, he said, he was responsible for what happened.

Email and text messages were obtained Wednesday by The Associated Press and other news organizations amid a statehouse investigation into whether the lane closings that led to the tie-ups were retribution against the mayor of Fort Lee for not endorsing Christie for re-election last fall.

"Time for some traffic problems in Fort Lee," Kelly wrote in August in a message to David Wildstein, a top Christie appointee on the Port Authority of New York and New Jersey.

A few weeks later, Wildstein closed two of three lanes connecting Fort Lee to the heavily-traveled George Washington Bridge, which runs between New Jersey and New York City.

Fort Lee Mayor Mark Sokolich called it "appalling" that the traffic jams appear to have been deliberately created.

Christie said he would go to Fort Lee today to apologize to Sokolich.

Kelly hasn’t commented, and Christie said he hadn’t spoken to her since the emails were released.

Beyond the specifics of the lane closures, critics suggest the incident reflects a darker side of Christie’s brand of politics that contradicts the image he’d like to project as he eyes the presidency.

The governor repeatedly sidestepped criticism that he bullied adversaries in an overwhelming re-election victory in November. Facing a little-known and underfunded opponent, he cast himself as a different kind of Republican: a compromising, consensus builder who ultimately earned strong support from minorities, union members and even many Democrats.

It was described as the opening argument for Christie’s prospective White House run. That argument is now clouded, at least temporarily, during one of the most important transitions of his political career.

In less than two weeks, he is scheduled to celebrate his second inauguration in the shadow of the Statue of Liberty on historic Ellis Island, a symbolic beginning to a second term designed to expand Christie’s bipartisan appeal. He also is expected to unveil his second-term priorities — solidifying his presidential resume — in a state-of-the-state address later this month, while beginning an aggressive national travel schedule as chairman of the Republican Governors Association.

Wildstein, a childhood friend of the governor, is scheduled to testify later today before a state Assembly committee. He asked a judge today to squash the subpoena, but the judge refused to do so.

Democratic National Committee chair Debbie Wasserman-Schultz said the "revelations are troubling for any public official." But she said: "They also indicate what we’ve come to expect from Gov. Christie — when people oppose him, he exacts retribution. When people question him, he belittles and snidely jokes. And when anyone dares to look into his administration, he bullies and attacks."

Christie today said he also asked his choice for state GOP chairman, his former campaign manager Bill Stepien, to withdraw for consideration for the post because of the "callous indifference" he displayed in emails on the traffic jams.

Associated Press writer Steve Peoples in Washington contributed to this report.