"As a businessman I was always treated really well by the press... it wasn't until I became a politician that I realised how nasty, how mean, how vicious and how fake the press can be," Trump said in his address to the World Economic Forum gathering.
Some of the 1,500 delegates in the packed conference hall booed at those remarks, made during a question and answer session after an otherwise conciliatory address by Trump to the business world.
Speaking to reporters earlier as he arrived at the centre in the snowbound Swiss resort, Trump had specifically dismissed as "fake news" a bombshell report about him in the New York Times.
The newspaper cited four anonymous sources as saying that Trump had ordered the firing of Russia investigation special prosecutor Robert Mueller last year, but that he had to back off when the White House counsel threatened to resign.
Two demonstrators in white T-shirts protested quietly against Trump in the lobby outside the hall where he was speaking in Davos.
"Listen to him, denouncing fake news. This is what he does," said one of them, Anya Schiffrin, a professor at Columbia University and the wife of prominent US economist Joseph Stiglitz.
She wore a T-shirt with a printed slogan reading "Not My President."
The other demonstrator, Sasha Kramer, wore a T-shirt reading "Stand With Haiti" -- one of the countries reportedly targeted in recent foul-mouthed comments by Trump.
"I believe that this forum is about dialogue and I don't think we have been given an option to have dialogue with President Trump," Kramer told AFP.
"I stand for the friends and colleagues in Haiti who were deeply insulted by his hateful and racist statements."