WASHINGTON — U.S. Secret Service Director Randolph “Tex” Alles is leaving the Trump administration, the White House said, amid a shake-up in the upper echelon of the Department of Homeland Security.

White House press secretary Sarah Sanders said Trump has selected career Secret Service official James Murray to lead the agency, saying he will assume the role next month. She added Alles will be “leaving shortly.”

Alles’ departure stems from a personality conflict within the agency, three officials said, speaking on the condition of anonymity to discuss the personnel matter. The officials said it was unrelated to the resignation of Homeland Security Secretary Kirstjen Nielsen and a recent security breach at the president’s private club in Florida.

Still, it comes amid a spate of turnover across DHS that began last week when Trump withdrew his Immigration and Customs Enforcement director’s nomination to stay on permanently.

After Nielsen’s departure, an empowered Stephen Miller, the immigration hawk White House senior adviser, is also eyeing the removal of Lee Francis Cissna, according to two of the people. Cissna is director of U.S. Citizenship and Immigration Services, which runs the legal immigration system.

Alles, a former Marine general who had no prior ties to the Secret Service, was recommended to the post by former White House chief of staff John Kelly. He had been the acting deputy commissioner of Customs and Border Protection.

Confirmed in 2017, Alles inherited an agency that had been dealing with a series of security and personnel issues. Weeks before he was nominated, a man jumped the White House fence and spent 15 minutes roaming the grounds.

His appointment was set to fulfill the recommendations of a group of former senior government officials that reviewed the Secret Service in 2014 and found that it was an “insular agency” in need of an outsider to lead it. But Alles’ unfamiliarity with the agency led to conflicts, said the officials.

Murray, has served as the special agent in charge of the agency’s Washington field office and the deputy assistant director of its office of protective operations.

Sanders said Alles “has done a great job at the agency over the last two years,” and that Trump is thankful for his service.