Brazil's ex-President Luiz Inácio Lula da Silva will be jailed while he appeals against a graft conviction, the Supreme Court has ruled.
Rafael Guedes told journalists that the order will "put the spotlight even more on the ex-president".
Justices on Brazil's top court have begun reviewing a request from former President Luiz Inacio Lula da Silva to stay out of jail while he appeals a corruption conviction.
However, in January, an appeals court unanimously increased the sentence to 12 years, the report said.
The court showdown in the capital Brasilia is a key battle for Brazil's deeply polarised electorate ahead of the October polls, in which Lula is now the heavy favourite, despite his legal problems.
Da Silva, who is known commonly as Lula, was convicted of corruption and money laundering last July and was and sentenced to nearly 10 years of imprisonment.
Lula is bidding to stage a return to office and has been leading in opinion polls ahead of the October election, but his failure to get his conviction quashed had already made disqualification from running from office virtually inevitable.
Critics said General Eduardo Villas Boas' statements on Twitter placed undue pressure on the court and were insensitive to the military's past role in ousting democratically-elected governments in Brazil.
They argue that Brazil's legal system has allowed many offenders to remain free, guaranteeing impunity for those able to afford lawyers for marathon procedural appeal processes.
"It was applied to only one person", she said.
Da Silva, president between 2003 and 2010, is the latest of many high-profile people to be ensnared in possibly the largest corruption scandal in Latin American history.
Investigators uncovered a major scheme in which construction companies essentially formed a cartel that doled out inflated contracts from state oil company Petrobras, paying billions in kickbacks to politicians and businessmen.
The leader is yet to be tried for several other corruption charges against him.
He was convicted past year of helping a construction company get sweetheart contracts in exchange for the promise of a beachfront apartment. The Supreme Federal Tribunal's decision means Silva will not only be forced to start serving the sentence, but will also stall his plans to run for re-election this year.
"The Brazilian people have the right to vote for Lula, the candidate of hope", it read. The conviction was handed down by Judge Sergio Moro, who is presiding over cases involving the so-called "Car Wash" investigation.
Lula's conviction was upheld on a first appeal.