Facebook has taken down another 115 accounts likely linked to foreign powers just hours before the opening of the U.S. midterm election polls, The social networking giant disclosed Monday night that it had acted on a tip from U.S. law enforcement.

“Our very early-stage investigation has so far identified around 30 Facebook accounts and 85 Instagram accounts that may be engaged in coordinated inauthentic behavior,” the company’s head of cybersecurity policy Nathaniel Gleicher said in a blog post Monday night. “We immediately blocked these accounts and are now investigating them in more detail.”

Nearly all of the Facebook pages linked to the accounts taken down were in Russian or French, whereas most of the Instagram accounts were posting in English. Some of those Instagram accounts were posting on political subjects, whereas others were publishing celebrity-related content.

Facebook wasn’t ready to definitively point to a culprit for this latest effort, with Gleicher saying that the company decided to act quickly because of the election. However, the company’s statement seemed to suggest that Russia may be a likely source.

Facebook’s former chief security officer Alex Stamos suggested in a tweet that the accounts may be linked to Russia’s Internet Research Agency (IRA). “From description of content, could be early-stage IRA-style operations meant to build audience,” he said in a tweet.

The social media giant has taken down hundreds of accounts over the past several months, with some linked to Russia, while others were linked to disinformation campaigns originating from Iran. The company has also set up a war room in its office in Menlo Park, Calif. to work on election protection. However, critics argue that social media companies still don’t do enough to fight election interference.

Reporting by Variety