Television personality Sean Hannity speaks to members of the audience while signing autographs before the start of a campaign rally in Cape Girardeau with President Donald Trump. Picture: Jeff Roberson/AP

Washington - Facebook said Monday it had blocked 115 accounts which could be linked to "foreign entities" on the eve of the US 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," Facebook's Head of Cybersecurity Policy Nathaniel Gleicher wrote in a statement.

The social media giant said that it has blocked 30 Facebook accounts and 85 on Instagram "that may be engaged in coordinated inauthentic behaviour."

"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," the statement said, adding that while some of these accounts focused on political debate.

The company said that the investigation into the activity is at a "very early stage," but with the elections fast approaching, the tech giant wanted to "let people know" about what actions have been taken.

The midterm election puts a third of senators and the entire House of Representatives up for a vote.

In August, administration officials acknowledged that that the threat of foreign influence in US elections is pervasive and ongoing.

Officials at the time stressed that US President Donald Trump's administration was taking steps to actively confront cybersecurity threats, including attempts to influence elections through social media.

Facebook remains under pressure over inflammatory content, coordinated disinformation campaigns and data breaches on its platform.

dpa