BRASILIA, Nov 1 (AFP) - Brazilian President Jair Bolsonaro on Tuesday did not concede defeat in his first public remarks since losing Sunday's election, saying protests by his supporters were the fruit of "indignation and a sense of injustice" over the vote.

However, he stopped short of contesting the election result and authorized his chief of staff, Ciro Nogueira, to begin the transition process with representatives of leftist President-elect Luiz Inacio Lula da Silva.

It took Bolsonaro, a right-wing nationalist, more than 44 hours to comment after the election was decided by electoral authorities, with the delay raising fears he would seek to cast doubt on the narrow result.

Amid his silence, supporters blocked highways to protest his defeat, with some calling for a military coup to stop former president Lula from returning to power.

The highway blockades have disrupted fuel distribution, supermarket supplies, and the flow of grains exports to major ports, according to industry groups.

In his brief national address, Bolsonaro joked that journalists would miss him, thanked those who voted for him and said he would abide by the constitution, which stipulates a transition of power on Jan. 1.

"The current popular movements are the fruit of indignation and a sense of injustice about the way the electoral process took place," he said.

He said protesters should avoid destroying property or "impeding the right to come and go," but did not tell them to go home.

"Bolsonaro has not put out this fire. He spoke to his hardcore supporters without criticizing the demonstrators on the highways," said political risk analyst Andre Cesar at Hold Legislative Advisors in Brasilia. "He is keeping his more extremist followers mobilized."

Karina Laurinda, 34, who took part in highway demonstrations outside of Sao Paulo, said she would keep protesting.

"Even if he says to calm down, not to react, we're still going to react because we won't accept a Lula government," she said.