US President Donald Trump. REUTERS/Carlos Barria Prominent investigative journalist Carl Bernstein says President Donald Trump's administration is in chaos less than two weeks after Trump took office.

"It's apparent to all but his most serious defenders and those who are his greatest advocates," Bernstein said on CNN on Monday night.

"Republicans on Capitol Hill who I'm talking to who are doubting his abilities," Bernstein said, "doubting even his stability under pressure. This is an extraordinary series of events."

Bernstein helped uncover the Watergate scandal in the 1970s that resulted in the resignation of President Richard Nixon.

Trump on Monday night fired acting US Attorney General Sally Yates over her refusal to enforce his executive order on immigrants and refugees. That happened after a weekend of dissent from both sides of the political aisle since Trump signed the order on Friday.

While Bernstein said Trump was "within his rights" to dismiss Yates, he added "it was not wise that he did."

Hundreds of thousands of people have flooded the streets in the US and abroad protesting Trump's executive order, dubbed a "Muslim ban" by prominent critics because the order specifically applies to immigrants from seven majority-Muslim countries.

Bernstein continued:

"[Trump] has obstructed the most basic of American principles of what we stand for as a country in terms of immigration: a nation of immigrants. These are authoritarian pronouncements that he has been making for days now, and it's starting to haunt him."

Aside from the immigration executive order, Trump in the first 10 days of his presidency has rhetorically rumbled with lawmakers, heads of state, and the press — and it's all happening under the specter of Trump's historically low 43% approval rating.