Brasilia, June 11 (NNN-RHC) -- Brazil's political parties launched their primaries to elect candidates for the upcoming general elections in October.

According to the Superior Electoral Tribunal (TSE), parties have until June 30th to elect their candidates for the offices of the nation's president and vice president, as well as state governors and deputy governors, senators, and federal, state and local deputies.

Some 140 million Brazilians are eligible to vote on October 5th, with runoffs slated for October 26th should they be needed.

Brazil's Democratic Labor Party (PDT) unanimously voted to back President Dilma Rousseff's reelection bid, even though several party leaders had earlier said the PDT should elect a candidate from its own ranks.

The PDT was Rousseff's first political party, but she now belongs to the Workers' Party (PT), which will officially announce Rousseff as its candidate when it holds its primary convention on Saturday, June 21st, in Brasilia.

Another leading political force, the Brazilian Democratic Movement Party (PMDB) -- which has the largest majority in congress and is headed by Vice President Michel Temer -- also voted to back Rousseff, with Temer as her running mate, with 59 votes in favor and 41 against.

Rousseff leads the polls as the favorite to win the presidential elections.