WASHINGTON — Facebook said on Tuesday that it had identified a coordinated political influence campaign that was potentially designed to disrupt November’s midterm elections, with the social network detecting and removing 32 pages and fake accounts that engaged in activity around divisive social issues.
The Silicon Valley company did not definitively link the campaign to Russia. But Facebook officials said some of the tools and techniques used by the accounts were similar to those used by the Internet Research Agency, the Kremlin-linked group that was at the center of an indictment this year alleging interference in the 2016 presidential election.
“At this point in our investigation, we do not have enough technical evidence to state definitively who is behind it,” said Nathaniel Gleicher, Facebook’s head of cybersecurity policy. “But we can say that these accounts engaged in some similar activity and have connected with known I.R.A accounts.”
The jolting disclosure, delivered to lawmakers in private briefings on Capitol Hill this week and in a public Facebook post on Tuesday, underscored how behind-the-scenes interference in the midterm elections has begun. In recent weeks, there have been reports of other meddling, including a Daily Beast report that the office of Claire McCaskill of Missouri, one of the Senate’s most vulnerable Democrats up for re-election this fall, was unsuccessfully targeted by Russian hackers last year, which Ms. McCaskill confirmed. American intelligence officials have indicated that at least one other unnamed Democratic senator up for re-election has been targeted.
Facebook’s announcement on Tuesday was a proactive tack to ward off a major national security threat. Company officials said they were working with the Federal Bureau of Investigation and other intelligence agencies on the matter. And Sheryl Sandberg, Facebook’s chief operating officer, and other executives mounted a media blitz after the announcement to explain what the company did and did not know about the influence campaign.
Those actions were a far cry from last year, when the social network was widely criticized for failing to detect Russian interference in the 2016 election. It took Facebook executives months to acknowledge the extent of the Russian operation, and release information connected with their investigation.
Since then, Facebook and its chief executive, Mark Zuckerberg, have been under siege from lawmakers and regulators for other scandals including data misuse, a misinformation epidemic and allegations of political bias. Last week, the company lost more than $120 billion in market value as it projected it would spend more money on moderation and security.
Hogan Gidley, a White House spokesman, did not directly address Facebook’s findings with reporters aboard Air Force One on Tuesday, but he said President Trump had “made it clear that his administration will not tolerate foreign interference into our electoral process from any nation state or other malicious actors.”
Earlier on Tuesday, Mr. Trump declared again on Twitter that there had been “No Collusion” between his campaign and the Russians, and asserted that, in any case, “collusion is not a crime.”
Lawmakers from both parties quickly set aside questions of who had perpetrated the influence campaign and said Facebook’s disclosure only clarified what they had feared since the extent of Russian involvement in 2016 became clear more than a year ago: that social media companies would be unable to keep up with the pace and scope of malicious efforts to abuse their platforms.
Senator Mark Warner of Virginia, the top Democrat on the Intelligence Committee, praised Facebook on Tuesday for bringing the activity out into the public, but asked for its cooperation in updating laws to prevent influence campaigns.
“Today’s disclosure is further evidence that the Kremlin continues…
