President Donald Trump announced his pick to become the next head of the Immigration and Customs Enforcement agency in a tweet Sunday.

Former Border Patrol Chief Mark Morgan will take over ICE, the president said. Morgan ran the Border Patrol in the final year of the Obama administration before being replaced when Trump took office.

"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. Mark is a true believer and American Patriot. He will do a great job!" the president said in his tweet.

A former FBI agent, Morgan was the first and so far the only outsider to lead the Border Patrol. He clashed with its union, which has a strong relationship with Trump. Morgan has expressed support for Trump's proposed wall along the U.S.-Mexican border and defended other parts of the president's immigration policies as a guest on Fox News.

Trump took notice of Morgan's Fox News appearances and celebrated the support from the former Obama administration official in three tweets this year.

"Mark Morgan, Former Border Patrol Chief with great experience in Law Enforcement, really understands the subjects of Immigration and the Border. Thank you Mark!" Trump said in one tweet, along with a mention of "@foxandfriends."

And on April 15, Trump tweeted, "Mark Morgan, President Obama’s Border Patrol Chief, gave the following message to me: 'President Trump, stay the course.'"

Morgan's appointment requires Senate confirmation.

Pending Morgan's confirmation, Matt Albence will serve as the agency's acting director, Trump announced in a later tweet.

"Matt is tough and dedicated and has my full support to deploy ICE to the maximum extent of the law!" Trump said via Twitter.

Acting Homeland Security Secretary Kevin McAleenan said in a statement Sunday that Morgan’s "record of service is needed to address the crisis at the border and support the men and women of Immigration and Customs Enforcement."

The move is the latest in a series of changes at the Department of Homeland Security as the administration wrestles with an increasing number of migrants – largely Central American families seeking asylum – at the southern border.

DHS Secretary Kirstjen Nielsen stepped down last month, saying in her resignation letter that immigration laws "impeded our ability to fully secure America's borders." Last month, Trump withdrew the nomination of Ronald Vitiello to head ICE and declared he wanted to take America's immigration policies in a "tougher direction."

ICE, which was established after 9/11 with the core mission of preventing another terrorist attack on the U.S., has become a lightning rod for immigration rights activists. Among the agency's responsibilities are locating and detaining immigrants who entered the USA illegally. Some Democrats have backed activists' calls for the agency to be eliminated.

Contributing: The Associated Press

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