WASHINGTON, July 28 -- U.S. President Donald Trump tweeted Friday he had named John Kelly, secretary of Homeland Security, as the new White House Chief of Staff.

"I am pleased to inform you that I have just named General/Secretary John F Kelly as White House Chief of Staff," Trump said.

"He is a great American and a great leader. John has also done a spectacular job at Homeland Security," Trump said, adding that Kelly has been "a true star of my administration."

"I would like to thank Reince Priebus for his service and dedication to his country. We accomplished a lot together and I am proud of him!" Trump said of his outgoing chief of staff.

For his part, Priebus said in a statement that he will "continue to serve as a strong supporter of the President's agenda and policies," and that he "can't think of a better person than General John Kelly to succeed me."

Priebus told news outlet CNN that he had resigned Thursday and was accepted by Trump.

Priebus said the president wanted go "a different direction" and that it was "a healthy thing."

In regard to a recent attack levelled by the new White House Communications Director Anthony Scaramucci, Priebus said it "was over" and that he had "moved on."

White House Press Secretary Sarah Sanders told the press that talks of Priebus' departure started two weeks ago, and that it had nothing to do with Scaramucci.

The resignation of Priebus came a week after Trump recruited Scaramucci as the communications director and the subsequent resignation of White House Press Secretary Sean Spicer.

Scaramucci has openly accused Priebus of leaking inside information to the press and threatened to contact the Federal Bureau of Investigation and the Department of Justice to shore up the leaks.

Priebus is the fourth high level White House official that has left the Trump administration since inauguration.

Before Spicer and Priebus, former National Security Advisor Michael Flynn resigned in February over allegations of improper contacts with Russia, and former White House Communications Director Mike Dubke resigned in May.

Kelly, 67, is a retired four star general of the Marine Corps and was tapped to lead the Department of Homeland Security on Jan. 20.

Kelly enjoyed bipartisan support, and was credited in his tenure as secretary of Homeland Security for reducing illegal border crossings and enforcing travel bans targeting citizens of six Muslim countries.

Elaine Duke, deputy secretary of Homeland Security, will be acting chief of the department.