President Donald Trump is tapping a former border patrol chief who served in the Obama administration to lead Immigration and Customs Enforcement, the AP reports. Trump tweets that Mark Morgan "will be joining the Trump Administration as the head of our hard working men and women of ICE." He added: "Mark is a true believer and American Patriot. He will do a great job!" The announcement comes amid a shake-up at the Department of Homeland Security triggered by the president's frustration with the increasing number of migrants at the border. Trump withdrew his previous nominee last month. Morgan, who was named the head of the US Border Patrol in 2016, was ousted early in Trump's presidency. He has been a guest on Fox News, defending Trump's immigration policies.