Thousands of bots originating in Russia and Iran - besides those created in the US -- were active during the 2018 November midterm elections, claims a study.
The research conducted by the University of Southern California's Information Sciences Institute and a Swiss researcher revealed that in virtually every US state, more than a fifth of those posting about the elections on Twitter in the weeks before Election Day were robots, news channel CNBC reported on Monday.
More than 15,000 Twitter bots used the #ivoted hashtag on Election Day, the findings showed.
The results, based on an analysis of millions of Twitter posts, suggest that accounts-linked to Russia and other foreign countries continued their activities during the US elections despite protective measures taken by social media platforms after allegations of Russian interference in the 2016 US presidential elections rocked the nation.
Twitter, for example, confirmed it had removed 10,000 bots pretending to be Democrats days before the midterms.
Twitter, Facebook and Google's parent company Alphabet removed hundreds of accounts tied to Iran in August 2018.
But the new research revealed that between October 6 and November 19 -- nearly two weeks after Election Day -- more than 200,000 bots were posting about the midterm elections, compared to about 750,000 humans.
To identify which accounts were bots, the researchers used a sophisticated tool called "Botometer" which uses Machine Learning (ML) techniques to determine whether an account is operated by a human or by a software algorithm, said the CNBC report, adding that the tool was developed at the University of Indiana.
Thousands of those bots could be traced to Russia and several hundred originated in Iran, according to one of the authors of the study, Emilio Ferrara of USC's Information Sciences Institute.