White House Press Secretary Sean Spicer stepped down Friday, ending his brief tenure as President Donald Trump's chief spokesman as the six-month-old administration suffers from low approval ratings.

The White House named Sarah Huckabee Sanders, Spicer's deputy, as the new White House press secretary.

Spicer quit in protest over the hiring of Anthony Scaramucci, a Wall Street financier, as new White House communications director, according to U.S. media reports.

Spicer was not happy about Trump's decision and he had doubts about Scaramucci's ability to do the job, NBC News reported, quoting sources with direct knowledge of the situation.

The shake-up on the communications team comes as Trump has been struggling to push forward his agenda such as repealing his predecessor Barack Obama's health care law, as well as massive tax cuts and infrastructure spending as part of his stimulus plans.

It was not known whether the shake-up will improve the public image of the administration, especially when investigations into the allegation that Trump associates colluded with Russian operatives to help the real estate mogul win the 2016 presidential election continue to dog the Trump White House.

Spicer said in a Twitter post that it had been an "honor" and "privilege" to serve Trump and the country.

Trump said in a statement that he is "grateful for Sean's work on behalf of my administration and the American people."