SAO BERNARDO DO CAMPO (Brazil) • Former Brazilian president Luiz Inacio Lula da Silva has turned himself in to the police, ending a day-long stand-off to begin serving a 12-year prison sentence for corruption that derails his bid to return to power.

Lula was flown by police to the southern city of Curitiba - where he was tried and convicted late last year - and then taken to the federal police headquarters last Saturday to serve his sentence.

Protesters supporting the former leader clashed with police outside the building. The police used stun grenades, tear gas and rubber bullets to disperse the crowd.

In a fiery speech hours earlier to a crowd of supporters of his Workers' Party outside the union building in Sao Paulo, Brazil's first working-class president insisted on his innocence and called his bribery conviction a political crime, but said he would turn himself in.

"I will comply with the order," he told the cheering crowd. "I'm not above the law. If I didn't believe in the law, I wouldn't have started a political party. I would have started a revolution."

Lula, who faces six more trials over corruption charges, ended the stand-off when he moved out in a convoy of the police's black sport utility vehicles after pushing his way out of the steel workers' union headquarters where he had taken refuge.

He entered police custody more than 24 hours after a court deadline last Friday afternoon.

Lula's imprisonment removes Brazil's most influential political figure and front runner from this year's presidential campaign, throwing the race wide open and strengthening the odds of a more centrist candidate prevailing, according to analysts and political foes.

Lula, 72, was convicted of taking bribes - including for the renovation of a three-story seaside apartment that he denies ever owning - from an engineering firm in return for help in landing public contracts.

A Brazilian Supreme Court justice last Saturday rejected the latest plea by Lula's legal team, which argued they had not exhausted procedural appeals when a judge issued the order for Lula to turn himself in.

Under Brazilian electoral law, a candidate is forbidden from running for office for eight years after being found guilty of a crime.

Rare exceptions have been made in the past, and the final decision would be made by the top electoral court if and when Lula officially files to be a candidate.

REUTERS