San Francisco (AFP)

Twitter issued a warning on Friday over a tweet from a prominent Democratic activist about Joe Biden's possible victory, declaring it premature, as the vote count continued in the United States amid protests from Republicans online and in the street.

"President-elect Joe Biden. Vice-President-elect Kamala Harris," tweeted Scott Dworkin, the founder of a Democratic committee dubbed the "Democratic Coalition Against Trump."

The social network, which has masked nearly one in two tweet from Donald Trump since Tuesday evening - the president assured, without proof, that he had won and that there was massive fraud - did not conceal the message but added the following note: "Official sources may not have yet determined the winner at the time this was tweeted."

Twitter, however, did not touch on many other similar tweets from Scott Dworkin on Friday as "ALERT: Joe Biden has been elected the 46th President of the United States of America".

"In accordance with our rules (...) on the elections, we will add mentions to tweets proclaiming victory, according to our criteria," a spokesperson for the platform told AFP.

The tweets likely to be pinned are those posted by accounts directly linked to campaigns for the 2020 election and which have at least 100,000 subscribers (or at least 25,000 "likes" on the post in question).

- Cite your sources -

"The results in Pennsylvania and in the presidential poll were only determined by one source. Until a second source has come to the same conclusions, proclamations of victory must cite their source," the spokesperson added. word.

Scott Dworkin quotes one of the sources recognized by Twitter, the firm Decision Desk HQ, specializing in the counts and projections of electoral results for the media.

The other sources are national news organizations such as ABC, CNN and Fox, and the Associated Press agency.

The Facebook communications team for its part clarified Thursday that it would post a notification at the top of its platform and Instagram with the presumed winner of the elections, as soon as "the Reuters agency and a majority of" decision desks "( expert panels responsible for announcing the election results) independent from major news outlets, including ABC, CBS, Fox, NBC, CNN and AP project the victory "of one of the candidates.

Platforms have struggled to stem the tide of false rumors, disinformation and calls for violence since the vote count began on Tuesday.

The problematic content comes mainly from the Republican candidate and his fans, disappointed to see the counters of Key States turn in favor of Joe Biden as the postal votes are counted.

"Our teams continue to take action against tweets that declare victory prematurely or contain misleading information about the election in general," Twitter recalled.

© 2020 AFP