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 law-enforcement veteran, got to know Mullin when he led an Oklahoma Highway Patrol security detail at the home of the then-U.S. senator.

The decision blindsided leadership at the Department of Homeland Security, including Mullin, who found out when the White House made its official announcement, according to a person familiar with the matter. The White House didn't 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 Senate 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 during an enforcement surge in Minneapolis, the Journal reported.

A senior White House official said that Schroyer's nomination was pulled after it became clear that it had stalled in the Senate.

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 and thousands of new recruits to carry out the agenda. The agency hasn't had a Senate-confirmed director since the Obama administration.

Mullin, who has sought to dial back the agency's profile since the operation in Minnesota, praised Schroyer as a "great pick" at the time the nomination was announced. Before Schroyer was tapped for the ICE job, Mullin hired him earlier this year as a senior adviser at DHS.