Pulitzer Prize-winning journalist Glenn Greenwald said Thursday he had resigned from The Intercept after the so called “US investigative media outlet” refused to publish his article critical of Democratic presidential nominee Joe Biden, and the evidence that he got bribe from China while he served as the US Vice President.

Greenwald, one of the first journalists to report on the Edward Snowden documents on US mass surveillance, said he was leaving the website he started in 2014 with two other journalists.

“The final, precipitating cause is that The Intercept’s editors, in violation of my contractual right of editorial freedom, censored an article I wrote this week, refusing to publish it unless I remove all sections critical of Democratic presidential candidate Joe Biden,” Greenwald said in a blog post.

Greenwald’s article accuses news outlets of pro-Biden bias in their stand-offish coverage of corruption allegations against the former vice-president’s son in a recent New York Post story.

The New York Post accused Hunter Biden of monetising access to his father in improper business dealings in Ukraine.

Twitter restricted the article’s spread amid questions over the “origins of the materials” on which it relied, including emails apparently sourced from a laptop left by Hunter Biden at a Delaware repair shop last year.

Facebook also restricted users ability on link to the article, saying – along with several US news outlets – that there were questions over its veracity.

Greenwald, 53, left The Guardian in 2013 to set up The Intercept with the founder of eBay, Pierre Omidyar.

He accused it of the “same trends of repression, censorship and ideological homogeneity plaguing the national press”.

But The Intercept hit back at Greenwald, dismissing him as “a grown person throwing a tantrum”, and said it was he who had allowed his standards to drop.

“While he accuses us of political bias, it was he who was attempting to recycle the dubious claims of a political campaign – the Trump campaign – and launder them as journalism,” the website said in a statement.

Greenwald, who lives in Brazil, shared the Pulitzer in 2014 for his reporting on leaks by former NSA contractor Edward Snowden about mass electronic surveillance programmes.