SAO PAULO, Aug. 4 (Xinhua) -- Brazil's Workers' Party announced on Saturday that for the sixth time in its history, ex-president Luiz Inacio Lula da Silva will be its candidate in the Oct. 7 presidential election.

Lula is currently serving a 12-year prison sentence for corruption, but he is the favorite in the polls.

This is the first time in Brazil's history that a person who is prisoned has been named as a presidential candidate.

The decision was made by the party's 600 delegates during its national meeting in Sao Paulo.

"This is a historic moment, Lula is officially our candidate," party president and senator Gleisi Hoffmann said.

Lula sent a message from his prison cell which was read during the gathering. In the message, Lula accused judge Sergio Moro, who presided over the Lava Jato case, of trying to "silence" him in order to stop his presidential run.

The Workers' Party must formally submit Lula's name to Brazil's Superior Electoral Court on Aug. 15. The court will decide whether to allow Lula as a candidate. The party has not yet named a vice-presidential candidate.

Jair Bolsonaro, candidate of the Social Liberal Party, is in second place in the polls.

If the court rules in Lula's favor, it would be his sixth time as a presidential candidate. He served as Brazil's president from 2003 to 2010.