Facebook said it blocked 115 accounts for suspected "coordinated inauthentic behavior" linked to foreign groups attempting to interfere in Tuesday's U.S. midterm elections.

The social media company shut down 30 Facebook accounts and 85 Instagram accounts and is investigating them in more detail, it said in a blog post late Monday.

Facebook acted after being tipped off Sunday by U.S. law enforcement officials. Authorities notified the company about recently discovered online activity "they believe may be linked to foreign entities," Facebook's head of cybersecurity policy, Nathaniel Gleicher, w...