Acting US attorney in Manhattan, NYC resigns after directive to drop case against Mayor Eric Adams

NEW YORK -- The top federal prosecutor in Manhattan resigned Thursday rather than obey a Justice Department order to drop corruption charges against New York City Mayor Eric Adams.

Danielle Sassoon resigned Thursday as the acting U.S. Attorney for the Southern District of New York. It follows days of tension between the US Attorney's office in Manhattan and the Justice Department.

Her resignation came days after a senior Justice Department official directed New York prosecutors to drop the case against Adams, who was accused of accepting illegal campaign contributions and bribes of free or discounted travel from people who wanted to buy his influence.

Sassoon sent a letter to Attorney General Pam Bondi informing her of her decision to resign. The letter was brief and did not mention the Adams case, according to a source familiar with the letter.

Sassoon just sent an email to her staff that said:

"Moments ago, I submitted my resignation to the attorney general. As I told her, it has been my greatest honor to represent the United States and to pursue justice as a prosecutor in the Southern District of New York. It has been a privilege to be your colleague, and I will be watching with pride as you continue your service to the United States."

Just Wednesday, Bondi expressed surprise upon learning that Sassoon had not yet followed her directive to file paperwork with a federal judge overseeing the mayor's corruption case to drop the charges.

And Deputy Attorney General Emil Bove admonished Sassoon over her repeated refusals to sign off on the dismissal.

"You lost sight of the oath that you took when you started at the Department of Justice by suggesting that you retain discretion to interpret the Constitution in a manner inconsistent with the policies of a democratically elected President and a Senate-confirmed Attorney General," Bove said in the letter obtained by ABC News.

Sassoon was briefly overseeing the U.S. Attorneys Office in the Southern District until the president's permanent nominee, Jay Clayton, is confirmed.

The Justice Department planned to remove the prosecutors handling the mayor's case and reassign it to the Public Integrity Section in Washington. However, as soon the Public Integrity Section was informed it would be taking over, John Keller, the acting head of the unit and his boss, Kevin Driscoll, the senior most career official in the criminal division resigned, according to multiple sources.

It is now unclear who will take over the Adams case and how soon it might be dropped, the sources said.

(The Associated Press and ABC News contributed to this report.)