Facebook said on Monday it had removed 68 pages and 43 accounts associated with a Brazilian marketing group, Raposo Fernandes Associados (RFA), for violating the social media network's misrepresentation and spam policies.
The newspaper O Estado de S. Paulo said the group was the main network of support for far-right presidential candidate Jair Bolsonaro on the Internet.
Bolsonaro is expected to win a runoff on Sunday in Brazil's most polarised election in a generation in which social media has become the main battleground between the candidates.
Facebook said RFA created pages using fake accounts or multiple accounts with the same names and posted massive amounts of clickbait intended to direct people to third-party websites.
"Our decision to remove these pages was based on the behaviour of these actors - including using fake accounts and repeatedly posting spam - rather than on the type of content they were posting," Facebook said in a statement.
It was not immediately clear how to contact RFA. Estado reported that owners of the company did not respond to requests for comment.
Facebook said it had detected spammers increasingly using sensational political content across the political spectrum to build an audience and drive traffic to their websites.
The company said the removal of the RFA pages was just one of many steps it had taken "to prevent bad actors from interfering with Brazil's elections on Facebook."
Facebook's popular messaging service WhatsApp has also come under scrutiny in Brazil after leftist presidential contender Fernando Haddad of the Workers Party accused Bolsonaro's supporters of using it for bulk messaging of misleading information during the campaign.
WhatsApp has more than 120 million users in Brazil, a country of nearly 210 million people, rivalling the reach of Facebook's main platform in one of the company's biggest global markets.
The messaging service has become one of the main ways Brazilians keep in touch with friends, colleagues and family, and also an important channel for getting political information. But WhatsApp has been flooded with fake news and conspiracy theories.
Haddad alleged on Monday that businessmen supporting Bolsonaro had been paying to bombard voters with misleading propaganda in violation of electoral law, which his rival denies.
WhatsApp said it took the allegations seriously and was "taking immediate legal action to stop companies from sending bulk messages," including sending cease-and-desist letters to the companies in question.
© Thomson Reuters 2018