Twitter slapped a fact check label on a pair of "misleading" tweets by President Donald Trump on Tuesday in which he railed against mail-in voting amid the COVID-19 pandemic.
"There is NO WAY (ZERO!) that Mail-In Ballots will be anything less than substantially fraudulent. Mail boxes will be robbed, ballots will be forged & even illegally printed out & fraudulently signed. The Governor of California is sending Ballots to millions of people, anyone living in the state, no matter who they are or how they got there, will get one," Trump tweeted.
"That will be followed up with professionals telling all of these people, many of whom have never even thought of voting before, how, and for whom, to vote. This will be a Rigged Election. No way!"
Experts who study the issue have found no evidence that voter fraud is a widespread problem in the United States.
Full coverage of the coronavirus outbreak
It appears to be the first time that the social media giant has fact checked Trump or otherwise enforced its terms regarding his tweets. Many of his critics have long called on Twitter to hold the president accountable for violating its terms of service.
The platform added language to the president's tweets that reads "Get the facts about mail-in ballots" and directs users to a Twitter article titled "Trump makes unsubstantiated claim that mail-in ballots will lead to voter fraud," along with a "What you need to know" section, as well as aggregated tweets about Trump's unfounded claims.
A Twitter spokesperson told NBC News on Tuesday that the tweets "contain potentially misleading information about voting processes and have been labeled to provide additional context around mail-in ballots."
The spokesperson added that the company rolled out a policy this month to combat misinformation, particularly related to the coronavirus pandemic.
Trump lashed out at Twitter on Tuesday, saying the company is restricting free speech.
".@Twitter is now interfering in the 2020 Presidential Election. They are saying my statement on Mail-In Ballots, which will lead to massive corruption and fraud, is incorrect, based on fact-checking by Fake News CNN and the Amazon Washington Post," he wrote in one tweet.
"Twitter is completely stifling FREE SPEECH, and I, as President, will not allow it to happen!" he said in another.
Brad Parscale, Trump's campaign manager, called Twitter biased in a statement Tuesday.
"We always knew that Silicon Valley would pull out all the stops to obstruct and interfere with President Trump getting his message through to voters," he said. "Partnering with the biased fake news media 'fact checkers' is only a smoke screen Twitter is using to try to lend their obvious political tactics some false credibility."
He added, "There are many reasons the Trump campaign pulled all our advertising from Twitter months ago, and their clear political bias is one of them."
Former Vice President Joe Biden, Trump's presumptive Democratic rival in November, urged the company to flag statements from every user, including Trump, when they are untrue.
"I think they should say when things are patently not true," Biden said Tuesday in an appearance on CNN when asked about Trump's recently sharing conspiracy theories on the site. "They should say so."
Download the NBC News app for full coverage of the coronavirus outbreak
In the wake of the COVID-19 pandemic, many states holding primaries have had to consider how to balance elections with public health. The pandemic has driven lawmakers to act, such as California Gov. Gavin Newsom, who issued an order that requires election officials in each of the state's 58 counties to send mail-in ballots to all registered voters.
However, the move has prompted legal challenges.
The Republican National Committee and other GOP groups, such as the California Republican Party and the National Republican Congressional Committee, sued Newsom on Sunday. RNC Chair Ronna McDaniel called Newsom's executive order "radical" and a "recipe for disaster that would create more opportunities for fraud."
A similar challenge also cropped up in Texas, but a federal judge there ruled in favor of the Democratic Party's expanding mail-in voting. The case is being appealed by state Attorney General Ken Paxton.
