The Justice Department also requested a list of agents involved in a U.S. criminal case against leaders of the Hamas militant group.

Brian Driscoll, the acting FBI director and head of the bureau's Newark field office, pushed back so aggressively that some feared he would be dismissed.

The FBI has provided the Justice Department with names of employees who worked on January 6-related cases after a new demand from the acting deputy attorney general, capping a weeklong back-and-forth between bureau leadership – who had sought to protect agent and staff identities – and the department.