The Trump administration has replaced the director of the FBI, Kash Patel, as the interim head of the Bureau of Alcohol, Tobacco and Firearms and installed Dan Driscoll, secretary of the army, in his place, according to two people familiar with the matter.

The abrupt change, which was announced to senior ATF officials on Wednesday morning, for the first time placed control of the embattled agency responsible for enforcing the nation’s gun laws to the defense department.

Patel has been running the FBI and the ATF for months, but it had proved to be overly burdensome, and Driscoll was selected to replace Patel as the interim head, as he was one of the few Senate-confirmed appointees available, one of the people said.

The initial move to have the FBI director run the ATF was unusual because the agency has traditionally had its own, separate director. The move to now transfer leadership outside the justice department entirely marks an additional departure.

Driscoll is expected to simultaneously run the ATF and continue with his current role. A spokesperson for the justice department did not respond to a request for comment about the long-term implication of the move.

Trump’s aides have viewed the ATF and its mission with skepticism and have discussed gutting the ATF or merging it with the Drug Enforcement Administration, another small and underfunded agency that has previously been part of the justice department.

The decision to have the army secretary run the ATF could be the precursor to such a move or at least to dramatically reduce its size and scope. In recent weeks, ATF agents have been diverted to help with enforcing Trump’s immigration agenda.

It also comes as Pam Bondi, the US attorney general who is under pressure from pro-gun groups, announced plans to eliminate the Biden-era ATF’s “zero tolerance” policy that strips licenses of firearms dealers found to have repeatedly violated federal laws and regulations.