RIO DE JANEIRO, April 5 (Xinhua) -- Thousands of citizens, including several left-wing leaders, rallied behind former President Luiz Inacio Lula da Silva on late Thursday.

Federal judge Sergio Moro had earlier in the day ordered Lula to surrender to the authorities and start serving his 12-year -prison sentence. He gave the former president a Friday deadline to turn himself in.

Lula was convicted of bribe-taking and money laundering. An appeals court also upheld the verdict.

According to Brazilian law, defendants can start serving their sentence before all appeals are judged. Lula's defense requested a habeas corpus for him to remain free until the last appeal was heard, but the request was rejected.

Thousands of people expressed their disagreement in a large political protest in Sao Bernardo do Campo, Sao Paulo State, where Lula started his political career. It is also the region where his Workers' Party has a strong base.

Supporters arrived at the headquarters of the Metallurgy Workers' Union building early evening. Several political leaders also showed up to express their support, including former President Dilma Rousseff, who succeeded Lula in office, and presidential candidates Guilherme Boulos and Manuela D'Avila.

Reports said the crowd prevented the police from getting access to Lula.

Rousseff, who was impeached in 2016, criticized the courts for depriving "the greatest president of this country's history of a right the Brazilian Constitution grants to all of us, which is freedom."

"They want to erase everything we have done for Brazil in 13 years," she said.

It remains unclear whether Lula will surrender on Friday since his defense has protested Moro's ruling, saying the former president could be arrested only after the deadline for all appeals in the Sao Paulo Federal Court, which will be next week.