Facebook says it has discovered a Russian-funded campaign to promote divisive social and political messages on its network, BBC reported Thursday.
The company said $100,000 was spent on about 3,000 ads over a two-year period, ending in May 2017.
The ads did not back any political figures specifically, but instead posted on topics including immigration, race and equal rights.
Facebook said it was co-operating with a US investigation into the matter.
It is handing over its evidence to special prosecutor Robert Mueller, who is overseeing an inquiry into alleged Russian interference in last year's US presidential election.
The advertisements directed users towards around 470 accounts that spread false information or were otherwise in breach of Facebook’s terms and conditions, the site said.
“The ads and accounts appeared to focus on amplifying divisive social and political messages across the ideological spectrum,” the company said in a blog post published on Wednesday.
The company said elsewhere it believed, but could not independently confirm, that the accounts were created by the so-called Internet Research Agency, a St Petersburg-based group known for posting pro-Kremlin messages on social media.
The accounts in question have now been shut down, Facebook's chief security officer Alex Stamos added.
The campaign was uncovered as part of Facebook's internal investigation into ways in which the network may have been abused during the last US presidential election campaign.
The site, and its founder Mark Zuckerberg, came under extremely heavy criticism for not taking the issue seriously in the days following US President Donald Trump's election win.
Mr Zuckerberg dismissed the notion that "fake news" on Facebook swayed the election as "crazy".