Luiz Inacio Lula da Silva is "in good spirits" despite his incarceration on corruption charges, says former Uruguayan President Jose 'Pepe' Mujica, who has visited the Brazilian presidential candidate in his detention center and delivered a message of encouragement to supporters.

Mujica met with Lula's followers on Thursday outside the Federal Police headquarters in Curitiba, where they have been camped out since the Workers' Party (PT) representative was taken into custody April 7 on corruption allegations.

The former Uruguayan leader praised the achievements realized during Lula's administration, as well as his international endeavors within Latin America.

"Under Lula, Brazil behaved like an older brother," Mujica said, adding that he found the candidate "in good spirits" but was worried for the future of Brazil and Latin America as a whole.

Mujica said Uruguay is concerned about the coming elections and Lula's fate. "For a small country flanked by gigantic Argentina and Brazil, when a neighbor shuts us out, we – Uruguayans – will catch a cold."

Earlier Thursday, Mujica transmitted a live video via social media addressed to Lula's supporters: "They can hold your body, but not your heart."

"There is a slogan there that says 'Lula Libre' (Free Lula); really, the mind can never be imprisoned. They can imprison your body, but not your heart, your mind. For whatever purpose, your mind is your heart, to go on beating for the control of Brazil... For this reason, Lula is free.

"This long fight didn't begin with you or us and it will not end with our lives… It's a shame that it almost takes a miracle to serve one''s country faithfully, but it is our fight."

Lula's 12-year prison sentence is widely viewed as a political stunt by the ruling right-wing government to block Lula from running for re-election.

The 72-year-old leftist politician insists he is innocent. Despite being incarcerated, Lula remains ahead in the presidential polls for Brazil's October presidential election. The PT has repeatedly said they will register Lula as their official candidate come August.