President Donald Trump followed the ouster of his Homeland Security secretary with another pink slip on Monday, reportedly axing the director of the U.S. Secret Service. Trump ordered acting White House chief of staff Mick Mulvaney to fire Randolph 'Tex' Alles. CNN first reported the move.

U.S. Citizenship and Immigration Services Director Lee Cissna is also leaving, according to CBS News. So are DHS undersecretary for management Claire Grady and general counsel John Mitnick.

A person with knowledge of USCIS's front office, however, said late Monday that Cissna was still in his job. And Alles told his agency's staff that he wasn't forced out.

White House Press Secretary Sarah Sanders said in a statement that 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.'

Alles wrote in a message to his agency that '[n]o doubt you have seen media reports regarding my "firing." I assure you that this is not the case, and in fact was told weeks ago by the Administration that transitions in leadership should be expected across the Department of Homeland Security.'

A White House official denied that DHS leaders beyond Alles and Nielsen left their jobs Monday or were fired. The official noted that DHS distributed a readout on Grady's trip to France for the upcoming G-7 Interior Ministers' meeting on Monday morning, indicating that she held her position as of 10:45 a.m.

The change at Secret Service comes on the heels of an embarrassing episode at Trump's private Mar-a-Lago resort club in Palm Beach, Florida, involving a Chinese national on a club guest list who was arrested with devices bearing computer malware. Secret Service punted responsibility to Mar-a-Lago's private security detail.

President Donald Trump fired U.S. Secret Service Director Randolph Alles on Monday, signaling a plan to toughen the ranks of officials tasked with carrying out his hard-edged border policy

Alles is pictured in the Oval Office with the president in April 2018; he fired Alles less than a day afte rdhowing Homeland Security Secretary Kirstjen Nielsen out the door

President Trump has been growing impatient with the speed and aggressiveness of his immigration policies' adoption

The twin killings of Nielsen adn Alles indicate the strong hand of 33-year-old Trump aide Stephen Miller, a former aide to then-Senator Jeff Sessions who has become the driving force behind the administration's immigration policy

Shoving Alles overboard and driving others out signals the growing authority of Trump adviser Stephen Miller, the 33-year-old former staffer to then-Sen. Jeff Sessions. Alles, Cissna, Grady and Mitnick were on a list of officials Miller targeted for removal as 'too soft,' accoding to a White House official.

A White House source with knowledge of the West Wing's goings on in the past week told DailyMail.com on Monday that Miller had advocated internally for Nielsen's firing, and for Alles to follow her out the door.

Miller is known as a sharp-tongued promoter of hawkish immigration policies that Democrats have complained push the boundaries of federal law and too often challenge court precedents.

Trump fired Nielsen in a tweet on Sunday shortly after meeting with her in the White House residence and hearing her plan for bringing U.S. immigration in line with legal boundaries.

Federal law dictates that as the third most senior Homeland Security official, Grady should have become 'acting secretary' after Nielsen's departure since the number two position is vacant.

Grady's decision to leave is significant because Trump chose to appoint U.S. Customs and Border Protection Commissioner Kevin McAleenan to manage the department until he nominates a permanent secretary.

By quitting now, Grady avoided what could have been a messy fight over who would emerge in charge on Thursday, the first full day after Nielsen leaves on April 10.

Homeland Security under secretary Claire Grady, pictured on Friday in Paris, was set to become acting secretary with Kirstjen Nielsen's departure, but she left instead – clearing the way for Trump's hand-picked 'acting' Kevin McAleenan

Homeland Security Department general counsel John Mitnick (left) announced his departure on Monday, along with Lee Francis Cissna, director of U.S. Customs and Immigration Services

In this artist sketch, a Chinese woman, Yujing Zhang, left, listens to a hearing Monday, April 8, 2019, before federal Magistrate Judge William Matthewman in West Palm Beach, Fla. Secret Service agents arrested the 32-year-old woman March 30 after they say she gained admission by falsely telling a checkpoint she was a member and was going to swim

Secret Service agents arrested Yujing Zhang, a Chinese woman, last week when she tried to enter Mar-a-Lago with two Chinese passports, a thumb drive with malware on it, four cellphones, a laptop and a hard drive.

Zhang's attorney Robert Adler said his client was entitled to be at the president’s private club because she paid $20,000 to attend what she thought was a party later that night – an event that earlier in the week had been cancelled.

'This receipt is evidence of a payment from Ms. Zhang to attend an event at Mar-a-Lago that night,' Adler told U.S. Magistrate William Matthewman of Zhang’s payment to Charles Lee, the alleged organizer of the canceled party.

Trump said shortly after the arrest that he was 'not concerned at all' about potential breach by Zhang, who posed for a picture with him at his Super Bowl party this year.

'Secret Service is fantastic. These are fantastic people. And the end result is it was good,' Trump said last Wednesday.

'The result is they were able to get her and she's now suffering the consequences of whatever it is she had in mind but I would say I could not be happier with Secret Service. Secret Service has done a fantastic job from day one. Very happy with them.'

A senior White House official said Monday that the Secret Service shift had been in the works for two weeks and was unrelated to the Mar-a-Lago incident.

Asked if Alles' firing was connected to Nielsen's or part of a broader Homeland Security Department housecleaning, another official said: 'Not that I'm aware of.'

White House Deputy Press Secretary Hogan Gidley said earlier on Monday that with an influx of illegal immigrants pouring into the U.S. from the south, 'tt's time to do things a little differently.'

Customs and Border Protection Commissioner Kevin McAleenan will temporarily replace Kirstjen Nielsen after her resignation takes effect

White House Deputy Press Secretary Hogan Gidley, pictured talking to reporters on Monday, said in a Fox News interview that President Trump hsa 'the right' to reshape his team

'And so the president is looking around to reshape his team so that he can have the people in place to carry out his agenda,' he said during a Fox News Channel interview. 'And quite frankly he has the right to do that.'

The Secret Service is best known for protecting the president and vice president and their families, and those who formerly served in office.

Established in 1865, the agency also investigates and prevents counterfeiting in order to protect the U.S. financial system, and combats computer-based financial crimes.

The Secret Service wasoriginaly a subagency of the Treasury Department, when it was principally an anti-counterfeiting force.

It became a branch of the Homeland Security Department in 2003 as the new post-9/11 agency coalesced around a mission that unified a group of previously far-flung government agencies.