(CNN) Facebook took down a network of Facebook pages and Instagram accounts Monday night after a tip from US law enforcement, just a few hours before polls open in this year's midterm elections.

"On Sunday evening, US law enforcement contacted us about online activity that they recently discovered and which they believe may be linked to foreign entities," Nathaniel Gleicher, the company's head of cybersecurity, said in a statement.

The company removed 30 Facebook accounts and 85 Instagram accounts.

"Almost all the Facebook Pages associated with these accounts appear to be in the French or Russian languages, while the Instagram accounts seem to have mostly been in English -- some were focused on celebrities, others political debate," Gleicher wrote.

"Once we know more -- including whether these accounts are linked to the Russia-based Internet Research Agency or other foreign entities -- we will update this post," he added.

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