Facebook and Twitter made a decision to limit links to a New York Post article critical of Democratic presidential candidate Joe Biden on Wednesday, in a move that President Donald Trump and conservatives slammed as "censorship."

In a story headlined "Smoking-gun email reveals how Hunter Biden introduced Ukrainian businessman to VP dad," the New York Post reported that it had obtained a computer abandoned by Biden's son Hunter tying the former vice president to Ukrainian energy company Burisma, where Hunter served as a board member.

"So terrible that Facebook and Twitter took down the story of "Smoking Gun" emails related to Sleepy Joe Biden and his son, Hunter," Trump wrote on Twitter.

Trump's campaign issued a statement saying that the emails were proof that Biden "lied to the American people" about his son's business dealings.

Joe Biden has denied any such involvement. Experts also say that the allegations are false, and questions have been raised about the article's sourcing.

As Biden's campaign denied he ever met the businessman in question, Burisma board advisor Vadym Pozharskyi, Facebook and Twitter placed restrictions on linking to the article, saying that there were questions over its truthfulness.

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"This is part of our standard process to reduce the spread of misinformation, said Facebook spokesperson Andy Stone.

"I want to be clear that this story is eligible to be fact-checked by Facebook's third-party fact checking partners. In the meantime, we are reducing its distribution on our platform," said Stone.

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Twitter said it was limiting the article's spread due to questions about the "origins of the materials" included in the article.

Users attempting to share the article received a warning message that their request could not be completed "because this link has been identified by Twitter or our partners as being potentially harmful." Those attempting to click on a link to the article also received a warning.

The New York Post subsequently reported that its primary Twitter account had been locked because its articles about Biden broke the network's rules against "distribution of hacked material."

Conservatives 'condemn censorship'

White House Press Secretary Kayleigh McEnany's personal Twitter account was also locked after she shared a link to the story.

"Censorship should be condemned," she wrote from her government Twitter page.

Republican Senator Josh Hawley, in a letter to Facebook chief executive Mark Zuckerberg, said the "seemingly selective" blocking suggests "partiality on the part of Facebook," while the New York Post called the social media outlets "propaganda machines" in an editorial.

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Hawley cited data showing that employees of Facebook and five other tech companies have donated nearly $5 million (€4.3 million) to Biden's campaign, and just $239,000 to Trump. 

The story focused on an email from April 2015, in which Burisma's Vadym Pozharskyi thanks Hunter for inviting him to a Washington meeting with his father. However, there was no indication of when the meeting was scheduled or whether it happened.

"We have reviewed Joe Biden's official schedules from the time and no meeting, as alleged by the New York Post, ever took place," the Biden campaign said.

lc/dr (AFP, Reuters, dpa)