Democratic presidential candidate, former Vice President Joe Biden speaks about the economy during an event in Dover, Del., Friday, June 5, 2020. (AP Photo/Susan Walsh)
CNN  — 

Joe Biden’s campaign is escalating its attacks on Facebook over its decision not to remove misinformation and false political advertisements from its platform.

But the social media giant is refusing to change its approach, responding to Biden by pointing to President Donald Trump’s executive order intended to stop sites like Facebook from fact-checking political statements.

The presumptive Democratic nominee’s campaign on Thursday began a push it is calling #MoveFastFixIt, urging its millions of supporters to sign an open letter to Mark Zuckerberg, the Facebook co-founder and chief executive.

The letter calls on Facebook to implement rules that prohibit threatening behavior and lies about how to vote. It also proposes a two-week period before the election in which all political advertisements must be fact-checked before they appear on Facebook.

“We call for Facebook to proactively stem the tide of false information by no longer amplifying untrustworthy content and promptly fact-checking election-related material that goes viral,” the Biden campaign’s letter says. “We call for Facebook to stop allowing politicians to hide behind paid misinformation in the hope that the truth will catch up only after Election Day.”

It was the latest episode in the Biden campaign’s battle with Facebook that dates back to last year during the Democratic presidential primary, but now comes with higher stakes as Biden and Trump face off in the general election.

It comes the week after Biden’s campaign spent about $5 million on Facebook ads – including $1.6 million last Thursday alone – as he sharpened his criticism of Trump’s response to the protests ripping across the nation over the police killing of George Floyd in Minneapolis.

Facebook’s approach is a striking difference from Twitter, another popular social media network that has begun labeling some tweets – including those from Trump – as false or misleading. Facebook does some fact-checking on its site, but politicians are exempt from this.

Twitter has placed fact-check labels on Trump tweets that contained lies about mail-in ballots and appeared to encourage violence and appended a warning label that another Trump tweet amid protests over Floyd’s death that it violated the social media company’s policies against glorifying violence.

Facebook posted a response to Biden’s open letter on its website, comparing itself to broadcast television networks that are regulated by the federal government.

“We live in a democracy, where the elected officials decide the rules around campaigns. Two weeks ago the President of the United States issued an executive order directing Federal agencies to prevent social media sites from engaging in activities like fact-checking political statements. This week, the Democratic candidate for President started a petition calling on us to do the exact opposite,” Facebook’s response said.

“Just as they have done with broadcast networks – where the US government prohibits rejecting politicians’ campaign ads – the people’s elected representatives should set the rules, and we will follow them,” Facebook said. “There is an election coming in November and we will protect political speech, even when we strongly disagree with it.”

Top Biden aides quickly mocked Facebook’s response, accusing the company of undermining the democratic process upon which it said it would base its policies.

Characterizing Facebook’s response, Biden communications director Bill Russo tweeted that the company was basically saying: “There’s an election coming in November, and we will continue to amplify content that confuses people about how to participate in it.”

“What on *earth* is this @facebook statement??” tweeted Biden digital director Rob Flaherty. “Yes, both sides are pressuring them but they decided to relent to the one who is saying ‘I’d like to mislead voters with no checks.’”

CNN’s Donie O’Sullivan contributed to this report.