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By Vanessa Buschschlüter
BBC News Online Latin America editor, Rio
Brazil's far-right president, Jair Bolsonaro, is expected to speak in the coming hours - breaking the silence he has maintained since being defeated in Sunday's presidential election.
Tension has risen in the country after Mr Bolsonaro broke with the tradition of acknowledging defeat.
Some of his supporters are refusing to recognise the results, and have erected roadblocks across the country.
Police said they had cleared more than 300 roadblocks so far, but 267 remain.
Dozens of flights in and out of São Paulo's international airport had to be cancelled after a key access road was cut off by protesters.
Blockages have been reported in all but two states, causing considerable disruption and affecting food supply chains.
Travellers on busses reported running low on water and food as they spent hours stuck in queues.
The head of Brazil's Supreme Court, Alexandre de Moraes, said there was "a risk to national security" and ordered that the roads be cleared.
The blockades started shortly after Brazil's electoral authorities announced a narrow win for Luiz Inácio Lula da Silva in the run-off of the presidential election.
With all the votes counted, Lula had 50.9% of the valid votes against Mr Bolsonaro's 49.1%.
The result was announced just before 20:00 local time (23:00 GMT) on Sunday. Since then, Mr Bolsonaro has neither conceded defeat - nor challenged the results.
It is customary for the defeated candidate to congratulate the winner and no previous outgoing president has taken this long to contact their successor.
Normally very active on social media, Mr Bolsonaro has also remained silent on all his social platforms.
On Tuesday, the group representing highway police said the president's silence "was encouraging a section of his followers to block Brazilian roads".
It is not yet clear what the outgoing president will say in his speech, but Communications Minister Fábio Faria told Reuters news agency that Mr Bolsonaro would not contest the election result.
Combative statements from the president in the past - such as that "only God" could remove him from office - mean there is a tense wait for him to appear in public.
Before the election, he had repeatedly cast unfounded doubts on the voting system.
Close allies of Mr Bolsonaro however have congratulated Lula on his win, and the powerful speaker of the lower house of Congress, Arthur Lira, said that "the will of the majority, as it is expressed in the polls, can never be contested".
Congratulations also poured in from across the world, with US President Biden saying the win came "following free, fair and credible elections".
Members of Mr Bolsonaro's government have also been in touch with Lula's team to start working on the transition of power ahead of Lula's swearing-in on 1 January 2023.
And while Mr Bolsonaro is looking increasingly isolated politically, hardcore supporters appear emboldened by his failure to acknowledge defeat.
"We will not accept losing what we have gained, we want what is written on our flag, 'order and progress'," one protester in Rio de Janeiro told AFP news agency.
"We will not accept the situation as it is," the man added.
President-elect Lula, meanwhile, has been holding phone calls with world leaders, including US President Joe Biden, French President Emmanuel Macron and German Chancellor Olaf Scholz.
He also had an in-person meeting with Argentine President Alberto Fernández.