"United States Secret Service director Randolph "Tex" Alles has done a great job at the agency over the last two years, and the President is thankful for his over 40 years of service to the country", White House press secretary Sarah Huckabee Sanders said.
The news of Mr Alles' departure follows just a day after Kirstjen Nielsen announced that she was leaving her post as the secretary of the Department of Homeland Security, and the departure of at least two more top officials is expected imminently. The removal of Alles leaves the status of virtually every single top official at the DHS either vacant or in an acting capacity including CBP, ICE, FEMA and now the Secret Service.
The President in recent weeks empowered Stephen Miller to lead the administration's border policies "and he's executing his plan" with what amounts to a wholesale decapitation or the Department of Homeland Security leadership, the official says.
Further ousters from the agency were reportedly imminent.
Alles insisted he was not fired in a letter emailed to staffers at the Secret Service on Monday and revealed he was informed weeks ago that the Trump administration meant to execute "transitions in leadership" across DHS.
He expressed "regret" he was not able to address the department before the news broke.
Alles retired from the military in 2011 after a 35-year career as a major general. The White House and DHS did not respond to requests for comment.
Alles became the agency's head after a 26-year-old California man wearing a backpack managed to scale the fence along the southern side of the White House in March 2017 - the first such breach reported during Trump's presidency.
The Alles announcement marked the latest in a long line of firings, resignations and departures of senior officials in the Trump administration, a list that has included the secretaries of state, defense, homeland security, interior, veterans affairs and health and human services, the attorney general and numerous senior White House aides. Before that, he was acting deputy commissioner of U.S. Customs and Border Protection.
Cissna is director of U.S. Citizenship and Immigration Services, which runs the legal immigration system.
Trump was so frustrated about the surge in migrants that he announced he would cut off USA aid to Guatemala, Honduras and El Salvador.