Facebook said late Monday it had blocked more than 100 Facebook and Instagram accounts suspected of engaging in "coordinated inauthentic behavior" ahead of the US midterm elections.

The account suspensions were made after US law enforcement officials contacted Facebook Sunday evening about recently discovered online activity believed "may be linked to foreign entities," Nathaniel Gleicher, Facebook's head of cybersecurity policy, wrote in a blog post Monday.

"Given that we are only one day away from important elections in the US, we wanted to let people know about the action we've taken and the facts as we know them today," Gleicher wrote in his post.

Facebook, which has more than 2 billion users worldwide, has been under pressure by lawmakers to protect the integrity of elections. In 2017, the tech firm revealed it found evidence that Russians used the social network to meddle in the 2016 US presidential election and sow discord among Americans. Since then, Facebook has pulled down hundreds of accounts including some tied to influence campaigns by Iran. 

Facebook's investigation said it had identified around 30 Facebook and 85 Instagram accounts linked to the suspect behavior. Nearly all the Facebook pages appeared to be in French or Russian, while the Instagram pages were written mostly in English, Facebook said.

Facebook said it would provide further information on whether the accounts are linked to the Internet Research Agency, a group linked to Russian propaganda efforts.

Facebook declined to identify the law enforcement agency that alerted it to the suspect behavior.

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