The Governor in the US state of New Jersey, Chris Christie, has sacked one of his top aides linked to lane closures at one of the world's busiest bridges.

Deputy Chief of Staff Bridget-Anne Kelly is accused of engineering political payback against a New Jersey town mayor, who did not endorse Mr. Christie's re-election.

Mr. Christie said at a news conference on Thursday that he is "embarrassed and humiliated" by the accusations his office orchestrated last year's lane restrictions at the George Washington Bridge.

He said he made the decision to fire Ms. Kelly "because she lied to me".

Mr. Christie apologised to the people of New Jersey for what he said was his "failure as the governor of this state to understand the nature of this problem sooner than I did".

Ms. Kelly is the latest casualty in a widening scandal that threatens to upend Mr. Christie's second term and likely run for US President in 2016.

Documents show she arranged traffic jams to punish the mayor of Fort Lee.

On Thursday, the governor continued to deny knowing about the lane closings and previously said no one on his staff was involved.

He said he was stunned by the "abject stupidity that was shown".