Facebook has blocked 115 accounts federal authorities told it were acting suspiciously and might be "linked to foreign entities" and coordinating their activities. The online giant revealed the move in a blog post Monday -- the day before the all-important mid-term elections in the U.S.

In the post, Facebook Head of Cybersecurity Policy Nathaniel Gleicher said, "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.

"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. We immediately blocked these accounts and are now investigating them in more detail. 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."

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Gleicher added that Facebook would ordinarily be further along in its investigation of the accounts before going public about its moves but wanted to get the word out quickly since Election Day was at hand.

"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 concluded.

The Internet research Agency is a Russian-based entity caught up in Special Counsel Robert Mueller's February indictment of 13 Russian nationals and three companies. The indictment accused them of breaking U.S. laws to interfere with the 2016 presidential election. The defendants, Deputy Attorney General Rod Rosenstein said, conducted information warfare against the U.S. Twelve of the individual defendants worked at various times for Internet Research Agency.

U.S. tech companies are stepping up security and efforts to fight disinformation campaigns as online troublemakers including Russian groups try to divide voters and discredit democracy. Facebook's purge is part of countermeasures to prevent abuses like those used by Russian groups two years ago to sway public opinion ahead of the 2016 U.S. presidential election.

Last month, the company removed 82 pages, accounts and groups tied to Iran aimed at stirring up social strife in the U.S. and the U.K. Facebook carried out an even broader sweep in August, removing 652 pages, groups, and accounts linked to Russia and Iran.