Brazil's former president, Luiz Inácio Lula da Silva is starting a 12-year sentence for corruption after surrendering to police on Saturday evening.
It follows a two-day stand-off that saw him take refuge in a steelworkers' union building after missing a court deadline to hand himself in.
The 72-year-old walked out of the office in his hometown, near Sao Paolo, and was taken away by police cars.
Scores of supporters had earlier blocked his car from leaving the scene.
Lula maintains he is innocent, but said he would comply with the arrest warrant against him.
Footage on Brazil's GloboNews showed Lula and his bodyguards pushing through the crowd outside the union building, in the town of Sao Bernardo do Campo.
He was then flown by police helicopter to the southern city of Curitiba, where he will begin his prison sentence.
Demonstrators set off fireworks as the helicopter landed, and riot police fired tear gas to disperse the crowd. The fire department said eight people were slightly injured, one of them by a rubber bullet.
Lula was the frontrunner for October's presidential election, but his jailing leaves the race wide open.
The former metalworker and trade union activist is an iconic figure for the left in Latin America. He was the first left-wing leader to make it to the Brazilian presidency in nearly half a century.