Combo file photo shows John Kelly (L) on Capitol Hill in Washington D.C. on Jan. 10, 2017 and Reince Priebus (R) at the Republican National Committee's headquarters in Washington D.C. on Nov. 5, 2014. (Xinhua/Bao Dandan)

WASHINGTON, July 28 (Xinhua) -- The vicious infighting that has plagued the White House for months claimed Friday yet another victim: White House Chief of Staff Reince Priebus.

U.S. President Donald Trump broke the news via Twitter as he made his way back to Washington from an event in New York, saying that Priebus was out.

"I am pleased to inform you that I have just named General/Secretary John F Kelly as White House Chief of Staff," Trump said while still on board Air Force One.

"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."

With that the substitution was done.

Even though Trump said in a third tweet that he and Priebus "accomplished a lot together," and that he was "proud of" Priebus, but it is no secret in Washington that Priebus has long been sidelined in the Trump administration.

According to Sarah Sanders, the newly appointed White House Press Secretary, Priebus' departure has been brought up since two weeks ago, while Priebus said in an interview with CNN late Friday that it actually started months ago.

The president wanted to go "a different direction" and that it was "a healthy thing," Priebus said during the interview, adding that he handed in his resignation in private on Thursday.

Despite long running rumors and speculations, the rift between Priebus and Trump was made public only a week ago when Trump recruited New York financier and Trump loyalist Anthony Scaramucci as the White House Communications Director.

Priebus reportedly strongly opposed the pick but was unable to convince Trump. Sean Spicer, former White House Press Secretary and an ally of Priebus, packed his bags just as Scaramucci unpacked his.

Priebus and Scaramucci has had a thorny relationship since the early days of the administration, when Priebus was successful in blocking Scaramucci from a senior White House post.

The hostility between the two men erupted this week when Scaramucci lashed out at Priebus on various occasions, including on Twitter and through multiple on-the-record phone calls with the press.

"In light of the leak of my financial disclosure info which is a felony. I will be contacting @FBI and @Thejusticedept #swamp @Reince45," Scaramucci tweeted Wednesday, hinting Priebus has committed a felonious crime.

Scaramucci further accused Priebus of being responsible for the damaging leaks inside the White House, and went as far as using profane words against Priebus during a phone call with a reporter of The New Yorker magazine.

Sanders denied allegations that Scaramucci was the reason behind Priebus's leaving, while Priebus told CNN that whatever was between him and Scaramucci was over and that he had "moved on."

Having just hit its half-year mark, the Trump administration has already lost a number of senior officials, including former National Security Advisor Michael Flynn, former Federal Bureau of Investigation Director James Comey, former White House Communications Director Mike Dubke, former Deputy National Security Advisor Kathleen Troia McFarland and former White House Deputy Chief of Staff Kate Walsh.

The drain of senior officials was seen by Washington pundits as a signal that the Trump administration is shedding its ties to the Republican establishment, while bringing in more reinforcement from what has become known as the New Yorkers.

Trump's daughter Ivanka and son-in-law Jared Kushner both were said to have played a role in edging out Priebus, the former Republican National Committee chairman.

In addition to those that have left, more of Trump's top officials are said to be standing on shaky grounds.

Trump has repeatedly voiced his disappointment with Secretary of Justice Jeff Sessions for recusing himself from the Russian probe, saying Sessions would not have been offered the job if he knew Sessions was going to recuse himself.

National Security Advisor H. R. McMaster has made the watchlist, after his plan to send more troops to Afghanistan was turned down by Trump.

White House Chief Strategist Stephen Bannon may also be falling out of Trump's graces, as Scaramucci openly criticized him of trying to make a name for himself and diverting from the president's agenda.

The instability in Trump's administration has raised serious questions on whether Trump is capable of running a united team, especially after a resounding defeat on the hill Friday morning that has all but tarnished his bid to repeal and replace Obamacare, a major campaign promise.

In an editorial, The New York Times described the Trump administration as "flailing" and "ineffective."

The biggest challenge for Kelly, the incoming chief of staff, will be "to bring discipline to the president," it said.