WASHINGTON-The White House on Thursday withdrew the nomination of Lance Schroyer to lead U.S. Immigration and Customs Enforcement, a setback for Homeland Security Secretary Markwayne Mullin.

Schroyer's nomination had faced resistance on Capitol Hill and even from some within the administration, including White House border czar Tom Homan, who opposed the selection, The Wall Street Journal previously reported. Schroyer, a veteran of the Oklahoma Highway Patrol, led Mullin's security detail when Mullin was a senator.

The White House didn't immediately respond to a request for comment on the withdrawal.

There were early signs of trouble for Schroyer, especially after Sen. Rand Paul (R-Ky.), the chair of the Homeland Security and Governmental Affairs Committee, threatened to delay the confirmation hearing during a closed-door briefing with senior Homeland Security officials.

Paul, who also voted against Mullin's nomination for DHS secretary, said he wouldn't hold a hearing until he received more information about the shootings of two American citizens by immigration officers in Minneapolis, the Journal reported.

Trump announced Schroyer's nomination in June and urged the Senate to swiftly confirm him. The previous acting ICE director, Todd Lyons, stepped down at the end of May. David Venturella, a former private prison company executive and previous ICE career employee, has been serving as acting ICE director.

ICE has been the agency at the center of the president's mass deportation campaign and has received billions of dollars in new funding to carry out the agenda. The agency hasn't had a Senate-confirmed director since the Obama administration.