The U.S. Department of Transportation on Thursday said it took the extraordinary step of replacing the federal lawyers defending it in a lawsuit over New York City’s congestion pricing program, after accusing them of undermining the department’s bid to end the toll.

The move came after the Manhattan U.S. attorney’s office, which had been handling the case, said it mistakenly filed in federal court on Wednesday night a confidential memo that questioned the department’s legal strategy and urged a new approach.

In response, however, the department raised the possibility that the disclosure attempted to sabotage its efforts to halt congestion pricing. Transportation officials said they would transfer the case to the civil division of the Justice Department in Washington. The memo has since been removed from the public docket.

In the letter, dated April 11, the three assistant U.S. attorneys on the case warned that Sean Duffy, the transportation secretary, was using shaky rationale to end the tolling plan and was “exceedingly likely” to fail, the lawyers wrote.

The 11-page letter instead suggested that the department could build a stronger case if it sought to terminate the federal government’s approval of the tolling program “as a matter of changed agency priorities,” rather than stick with the previous tactic of questioning the legality of the toll.

It’s not unusual for lawyers to advise their clients confidentially in this way. But the filing telegraphed the government’s legal weaknesses in the middle of a tense fight with Gov. Kathy Hochul and transit leaders who have vowed to keep the tolling program running.