RIO DE JANEIRO (AFP) - Brazilians opposed to far-right politician Jair Bolsonaro started a Twitter trend by casting their ballots on Sunday (Oct 28) with books in hand - a jibe at Bolsonaro backers who posted selfies of themselves voting with firearms.

Pointedly picking their titles - like 1984, How Democracies Die, and How to Talk to a Fascist - opponents of the former army captain turned the hashtags #LivroSim and #ArmaNao (BooksYes, GunsNo) into trending topics on social media as Brazil voted in a divisive runoff election.

It was a tongue-in-cheek reply to Bolsonaro supporters who posted images of themselves voting with their guns during the first-round election on Oct 7.

Dubbed a "Tropical Trump" by some, Mr Bolsonaro has promised to relax gun-control laws so "good people" can take justice into their own hands, in a country fed up with violent crime.

"I took this book with me to vote. What about you?" voter Eliane Brum wrote on Facebook, posting a picture of herself with Portuguese writer Valter Hugo's book Dehumanisation.

"I brought two," another voter answered on Twitter, posting pictures of The Importance of the Act of Reading, by Brazilian educator Paulo Freire, and a book by Portuguese Nobel Prize-winner Jose Saramago.

The idea was a nod to the leftist candidate facing Mr Bolsonaro, Mr Fernando Haddad, an academic with degrees in law, economics and philosophy who was education minister under former president Luiz Inacio Lula da Silva.

It was also a subtle protest against the sometimes violent rhetoric used by Mr Bolsonaro, who has vowed to "cleanse" Brazil of leftist "reds", and once said a female lawmaker he opposed was "not worth raping".

That lawmaker - Ms Maria do Rosario, of Mr Haddad's Workers' Party - posted a selfie of herself voting with a book called Brazil: Never Again, a treatise on the country's brutal military dictatorship from 1964 to 1985.

Mr Bolsonaro is an unabashed admirer of the military regime, saying its "mistake" was that it tortured, instead of killing, leftist dissidents and suspected sympathisers.

Other titles that took a dig at Mr Bolsonaro's denigrating comments about women, gays and blacks included Women, Race, And Class by US civil rights activist Angela Davis, and biographies of Martin Luther King Jr and Malala Yousafzai.

Despite the opposition, Mr Bolsonaro won Brazil's presidential election on Sunday, riding a wave of frustration over corruption and crime that brought a dramatic swing to the right in the world's fourth-largest democracy.