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 U.S. attorney’s office for the Southern District, which had been handling the case, said it mistakenly filed in federal court in Manhattan 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.