Police are searching for other casualties, with officials warning the actual death toll could rise further.

Obama said the election was "the last best chance to at least rein in some of the foolishness of this administration".

Flávio Bolsonaro, the son of Brazil's imprisoned former president, is presenting a strong challenge to Lula, 80, who is seeking a fourth term in office.

Officials have so far managed to avoid a repeat of last weekend's rioting and looting as hundreds of thousands took part in demonstrations.