Zeid Ra’ad al-Hussein said Mr Trump had also made worrying remarks about women, Mexicans and Muslims, and went on to question the president’s approach to immigration and decision to pardon former Arizona lawman Joe Arpaio.
There was no immediate response from the White House on the wide-ranging rebuke of Mr Trump’s repeated references to the “fake media” and some other statements and decisions.
“It’s really quite amazing when you think that freedom of the press, not only sort of a cornerstone of the US Constitution but very much something that the United States defended over the years, is now itself under attack from the president,” the UN High Commissioner for Human Rights said.
“It’s sort of a stunning turnaround. And ultimately the sequence is a dangerous one,” he told a news conference in Geneva.
Referring to the ‘New York Times’, ‘Washington Post’ and CNN, he added: “To call these news organisations ‘fake’ does tremendous damage and to refer to individual journalists in this way, I have to ask the question is this not an incitement for others to attack journalists?”
He voiced concern that a journalist from the ‘Guardian’ had been “assaulted in the United States most recently”, but gave no details.
Mr Trump rounded on journalists last week, calling them “truly dishonest people” and criticising their coverage of a white supremacist-organised rally in Virginia and the political fallout from his comments that violence there was caused by “many sides”.
Mr Trump has also made worrying remarks about women, Mexicans and Muslims, “mocked a person with disabilities publicly” and issued a directive on a transgender ban in the military, said Mr Zeid.
“The president prides himself as a taboo breaker. But at the time I expressed my feeling this was grossly irresponsible, because it has consequences, it emboldens those who may think similarly to sharpen their assaults on these communities.”
Comparing the role of a US president to a bus driver, he said: “I almost feel the president is driving the bus of humanity and we’re careening down a mountain path.”