Brazil's center-left opposition Workers' Party (PT) on Saturday nominated Luiz Inacio Lula da Silva as its presidential candidate even though the former head of state is serving a prison term for corruption and will likely be barred from competing in the Oct. 7 balloting.

In its national convention in Sao Paulo, the PT named the 72-year-old Lula - the leader in voter preference at around 30 percent despite his legal woes and imprisonment in the southern city of Curitiba - as its candidate but did not choose his running mate.

In July 2017, the former head of state was found guilty of accepting bribes in exchange for helping Brazilian construction company OAS obtain lucrative contracts from state oil giant Petrobras and sentenced to nine years and six months in prison.

On Jan. 24, an appeals court voted unanimously to uphold that earlier verdict and increase Lula's prison sentence to 12 years and one month.

The three-judge panel ruled there was sufficient proof that Lula accepted the triplex in Guaruja, a resort town near Sao Paulo, from OAS in exchange for helping that firm secure contracts with Petrobras.

The case against Lula, who vehemently denies any wrongdoing, is based largely on plea-bargained testimony from people already convicted as part of a sprawling investigation into a bribes-for-inflated-contracts scheme centered on Petrobras.

Lula, a center-left former lathe operator and union leader, governed Brazil from 2003 to 2011 and left office with sky-high approval ratings.

Jurists say a 2010 Brazilian law known as Ficha Limpa (Clean Record) clearly states that a defendant whose conviction has been upheld by an appellate court is barred from competing for public office for eight years.