Facebook has discovered that bad actors are spreading misinformation on its service in prelude to the upcoming midterm elections.
The social networking giant said Tuesday that it removed 17 Facebook profiles, 8 Facebook Pages (the public Facebook profiles for organizations and celebrities), and 7 Instagram accounts that were exhibiting “inauthentic behavior.” Some of the now-removed Facebook Pages were titled “Aztlan Warriors,” “Black Elevation,” “Mindful Being,” and “Resisters.”
More than 290,000 Facebook accounts followed “at least one of these Pages, the earliest of which was created in March 2017,” the company said in a blog post.
Facebook said that the bogus Facebook Pages created 30 events since May 2017. The largest event hosted by one of the unspecified bogus Facebook Pages, “had approximately 4,700 accounts interested in attending, and 1,400 users said that they would attend.”
In a call with reporters on Tuesday, Facebook’s head of cybersecurity policy Nathaniel Gleicher said that of the 30 previous events hosted by the fraudulent pages, two events have not yet occurred, including one that was slated for Aug. 10, and another in January.
Regarding the events that have already transpired, Gleicher said that the company can only “assess what happened in Facebook” and “can’t address what happened in the real world,” which implies the possibility that people attended one of the events created by the bad actors.
Facebook (FB) chief operating officer Sheryl Sandberg said during the briefing that Facebook “will be informing people who said they would be interested” in attending the now-disabled Aug. 10 event, “No Unite the Right 2 – DC.”
Facebook executives said there are similarities between the bad actors and the Russian entities known as the Internet Research Agency (IRA) that spread misinformation on Facebook and other services to sow discord in the U.S. populace in prelude to the 2016 U.S. Presidential election. However, Facebook stopped short of pinpointing the actions to Russia or any particular group.
“We don’t have enough technical evidence to state definitively who’s behind this,” said Gleicher.
Facebook chief security officer Alex Stamos said that “some of the tools and techniques and procedures are consistent” with some of the IRA’s previous tactics, but the company doesn’t “feel the evidence is enough.”
That said, U.S. Senator Mark Warner pointed to Russia as responsible for the fraudulent Facebook accounts and Pages that were removed, and said in a statement on Tuesday that “Today’s disclosure is further evidence that the Kremlin continues to exploit platforms like Facebook to sow division and spread disinformation, and I am glad that Facebook is taking some steps to pinpoint and address this activity.”
Facebook executives said they have briefed law enforcement and intelligence agencies on the bogus accounts so that they can make their own determinations on which entity is responsible.
Get Data Sheet, Fortune’s technology newsletter.
Regarding whether the bad actors were trying to sow discord within particular communities belonging to the political left or right, Stamos said “we’re not characterizing the broad nature of this campaign,” but that Facebook will release additional samples of the type of content the bogus accounts were spreading.
Facebook released on Tuesday a small set of examples of the type of content the bogus Facebook accounts and Pages sent on the service.
In one post from 2017, the now-banned Resisters Facebook Page posted a job listing seeking a “part-time event coordinator” involved with organizing community events and activities intended to unite people upset with the current Donald Trump presidential administration.
The same Resisters group also shared an event titled “Trump Nightmare Must End” on Nov. 4, 2017 in New York City that showed more than 3,400 people were interested in going, with 520 indicating they were attending.
Stamos said that several of the now-banned accounts created content mentioning the U.S. Immigration and Customs Enforcement agency in light of President Trump’s controversial immigration policies that have led to some children being separated from their guardians. He said that Facebook discovered an event created by one of the bogus accounts “that was protesting ICE,” and that Facebook expects these bad actors to continue highlighting these kinds of hotly contested political issues.