In a surprise move, President Donald Trump announced on Sunday that he would nominate Mark Morgan, the former chief of U.S. Border Patrol under President Barack Obama, to serve as the new permanent director of U.S. Immigration and Customs Enforcement (ICE).

“I am pleased to inform all of those that believe in a strong, fair and sound Immigration Policy that Mark Morgan will be joining the Trump Administration as the head of our hard working men and women of ICE,” Trump tweeted. “Mark is a true believer and American Patriot. He will do a great job!”

Morgan had served only six days under Trump before submitting his resignation as head of Border Patrol, one day after Trump signed an executive order mandating the construction of a wall along the U.S.-Mexico border. Morgan has recently made appearances on Fox News, in which he supported the president’s immigration policies.

The former Border Patrol chief told Law & Crime in January that he had been pressured to resign from the position, in part because of his public opposition to the concept of a border wall, the keystone of Trump’s immigration agenda.

Asked by a U.S. Senate committee in November 2016 about Trump’s proposed wall, Morgan said that such a wall would not be “the sole answer,” and that it did not need to cover the full 2,000-mile border between the United States and Mexico.

Morgan has since come around to supporting the administration’s policies on immigration, including the as-yet-unbuilt wall.

“The current administration had decided to go in a different direction since the president was inaugurated,” Morgan said at the time. “The president is correct, and what he’s doing—the wall works, one hundred percent.”

In a discussion with Fox News’ Neil Cavuto in January, Morgan told the host that “we need to do it all, including the wall.”

“I agree one hundred percent with what the president is trying to do with al things related to border security,” Morgan said at the time. “It is absolutely, one hundred percent, in my opinion... a national security and humanitarian crisis.”

ICE declined to comment on the nomination, and White House did not immediately respond for clarification on whether Morgan’s nomination has been formally submitted to the Senate.

The nomination is the latest change in senior staff at the Department of Homeland Security, which has endured numerous shakeups in recent months as Trump has grown frustrated by the legal, political and, occasionally, ethical hurdles to implementing his hard-right immigration proposals. Former Homeland Security Secretary Kirstjen Nielsen stepped down in April following numerous reports that Trump felt she was slow-walking his agenda on border security, and Trump pulled the nomination of Ronald Vitiello to lead ICE two days earlier, declaring that he wanted a “tougher” nominee.

“Ron’s a good man,” Trump told reporters at the time. “But we’re going in a tougher direction. We want to go in a tougher direction.”