Truck drivers who support Brazil's outgoing President Jair Bolsonaro blocked roads in 20 states on Monday as Bolsonaro himself remained silent on losing the election.

The fallout from the election is threatening to drag into a second day after leftist former President Luiz Inacio Lula da Silva declared victory.

Official results showed Lula's margin of victory was narrow in percentage terms, at 50.9% to 49.1%. But with almost 120 million valid votes cast, that also equates to a winning margin of just over 2 million votes.

Lula said "the only winner is the Brazilian people" at his victory speech. He is set to be inaugurated on January 1.

Truckers halt traffic for Bolsonaro

Truckers staged more than 230 protests to partially or fully block roads in 20 states, Brazil's federal highway police said.

Video footage showed some truckers at roadblocks calling for a military coup to prevent Lula becoming president, as protests spread from the states of Mato Grosso and Santa Catarina to Parana, Sao Paulo, Minas Gerais, Goias and Bahia

The roadblocks in the farming heartland of Matto Grosso in particular threaten to disrupt agricultural shipments, said Normando Corral, president of the Famato farmers' federation.

"It's too soon to say if it's going to interfere with the flow of production, because the blockades started yesterday," he said. "I don't know how long it will last."

The access roads to certain harbors have also been blocked. However, port authorities in Santos and Paranagua said there was no immediate disruption to cargo movement.

Bolsonaro silent on election defeat

Bolsonaro has yet to publicly acknowledge his election defeat, although Reuters news agency reported that Communications Minister Fabio Faria said he would not contest his defeat and would address the nation later on Tuesday.

Bolsonaro spent the day after the election inside the presidential palace while reporters camped outside.

The prolonged silence has led to speculation as to whether Bolsonaro will concede defeat, or whether he will claim electoral fraud, since he baselessly questioned the reliability of the country's electronic voting machines in recent months.

His eldest son Flavio Bolsonaro — who is a senator himself — tweeted thanks to his father's supporters, adding: "Let's raise our heads and not give up on our Brazil! God is in charge!"

Several key Bolsonaro allies have publicly accepted the election results.

"He must have several plans for how to contest the results of the polls; the question is whether he has the political support to go ahead with these plans,'' Paulo Calmon, a political science professor at the University of Brasilia, told the AP news agency.

"He won't have the support of Sao Paulo's governor, of the Lower House, Senate, and he will have to face opposition from everyone."

zc/msh (Reuters, AP)