Thousands of automated bot accounts on Twitter have worked over the last eleven months to boost former president Donald Trump and attack his critics and 2024 competition, according to a new report.

Cyabra, an Israeli tech firm, told the Associated Press it discovered a network of fake accounts that appear to have been created within the U.S. by an unknown entity.

The bots have targeted former U.N. ambassador Nikki Haley, who is running against Trump for the 2024 Republican presidential nomination, as well as Florida governor Ron DeSantis, who is widely seen as Trump’s most formidable 2024 opponent despite having not yet joined the race.

Researchers say hundreds of thousands of bots across three different networks of Twitter accounts could be involved. The accounts were created in April, October and November 2022, according to the report. Researchers used patterns in an account’s profile along with its follower list and posts to identify bots, which usually post “repetitive content about the same topics,” according to the report.

“One account will say, ‘Biden is trying to take our guns; Trump was the best,’ and another will say, ‘Jan. 6 was a lie and Trump was innocent,’” Cyabra engineer Jules Gross told the AP. “Those voices are not people. For the sake of democracy I want people to know this is happening.”

Researchers said one measure of bot impact is the number of posts about a topic by fake accounts. For an average topic, that number is in the low single digits, but nearly three-fourths of the negative posts about Haley were made by fake accounts, according to the report.

The bots have also focused on seeding the idea that DeSantis would be more fit to serve as Trump’s 2024 running mate than as president.

“Our understanding of what is mainstream Republican sentiment for 2024 is being manipulated by the prevalence of bots online,” the Cyabra researchers concluded.

The news comes one month after a study from the New York University Center for Social Media and Politics found Russian efforts to influence the 2016 presidential election on Twitter reached relatively few users and had no measurable impact in changing minds or influencing voter behavior. Many Trump-critics and members of the mainstream media had suggested Trump’s 2016 win was the result of Russian meddling and that there was a sophisticated system of bots working to turn the tide in the Republican’s favor.