Two Israeli researchers said on Monday they had discovered a network of hundreds of fake Twitter accounts that promoted Prime Minister Benjamin Netanyahu and attacked his political rivals, a week before a national election.
No direct connection had been found between the network and Netanyahu or his right-wing Likud party, said the report, part of a project aimed at ridding social networks of manipulative practices.
Opinion polls show Netanyahu and his main challenger, centrist candidate Benny Gantz, locked in a close race ahead of the April 9 election.
Researchers Noam Rotem and Yuval Adam said fake names were used in more than 150 accounts in the network and hundreds more might also be bogus.
People, and not automated "bots," were behind the postings, the researchers said, naming one of the alleged operators, who denied through his lawyer involvement in any organised pro-Netanyahu network.
"Expert analysis shows the network has reached more than 2.5 million Israelis," the report said, putting the number of tweets since the start of the election campaign at more than 130,000. Israel has a population of about 8.7 million.
A spokeswoman for Twitter, asked by Reuters about the report, declined comment.
Likud party denies allegations
In response to the allegations, Likud denied using fake accounts and said Netanyahu would make a statement on the report later in the day.
In a video clip dismissing the report's findings, Likud said 985,408 Israelis had voted for Netanyahu in the previous election in 2015.
The report said one surge of fake tweets came after Israel's attorney general announced his intention in February to indict Netanyahu on corruption charges, which the prime minister has denied.
Another flurry, the report said, was launched after Gantz's Blue and White party kicked off its election campaign.
"There is a whole network here, funded by big money, for stealing the election," Gantz said at a news conference after the findings were released. "This matter demands investigation."
Rotem has been interviewed in the past by Israeli and international publications about cybersecurity and social media manipulation.