Twitter has suspended several fake accounts purporting to be African Americans who support US President Donald Trump and which had succeeded in garnering several thousand followers in just a few days.
"Our teams are working diligently to investigate this activity and will take action in line with the Twitter rules if Tweets are found to be in violation," a spokesman for the San Francisco-based company said on Tuesday.
Darren Linvill, a professor at Clemson University who specialises in disinformation on social media, published some examples of the fake accounts on Twitter, accusing them of using "digital black face".
Since he began tracking the accounts since Saturday, Mr Linvill found more than two dozen accounts that collectively had 265,000 retweets or Twitter mentions.
He told Reuters the accounts ranged in size but some had attracted tens of thousands of followers.
"Yes IM BLACK AND IM VOTING FOR TRUMP!" said one of the examples he shared, under the name of Ted Katya on 17 September. "Libs wont like that but I dont care!!!"
The tweet was shared 6,000 times and was "liked" more then 16,000 times.
Most of the accounts "used images of real Americans in their profiles," Mr Linville said, and some of them had tens of thousands of followers.
The accounts sometimes claimed to be owned by military veterans or members of law enforcement.
Twitter suspended the identified profiles because they were deceiving users about their intention and their identity and were therefore deemed to be manipulating public debate.
The company forbids using the platform "to artificially amplify or suppress information or engage in behaviour that manipulates or disrupts people’s experience on Twitter," according to guidelines published last month.
Twitter declined to specify the number of accounts suspended or to comment beyond its statement.
The Trump campaign did not immediately respond to a Reuters request for comment on the investigation, which was first reported by the Washington Post.
Mr Linvill told Reuters that most of the accounts were created in 2017, but had become more active in the past two months.
He said all the accounts he had been tracking in the group had now been suspended by Twitter, but the damage had already been done.
"It doesn't matter if Twitter's shutting you down in four days, they've already had their impact," Mr Linvill said.
Twitter declined to answer Reuters' questions about the origin of the accounts.
Under heavy criticism, social media platforms like Facebook and Twitter have mobilised in the run-up to the 3 November election to show they have learned the lessons of the scandals in 2016. Then, the platforms were used to spread false or misleading information ahead of the US elections, some of them concerted campaigns initiated by foreign powers such as Russia.
The platforms have made progress in dismantling large-scale disinformation campaigns but now face a number of smaller-scale attempts to disseminate falsehoods through accounts like those suspended on Tuesday.
The people behind such campaigns often use themes linked to current events and which inflame public opinion, such as the coronavirus or the Black Lives Matter movement, to draw in as many followers as possible.
