“I strongly condemn the attacks against the Supreme court and the lower house,” he said in a statement posted to X.
“We must know the motivation behind the attacks, and to re-establish peace and safety as fast as possible.”
Images carried by news agencies showed the deceased man lying in an area outside the court, as officers cordoned off the area.
A police spokesperson told AFP that they could “confirm that there is a body in front of the Supreme Court”, but offered no further details.
Brasilia’s Deputy Governor Celina Leao told reporters the explosion occurred after a man approached the entrance to the court and failed to gain entry, and recommended parliament remain closed on Thursday while investigations continued.
“It could have been a lone wolf, like others we’ve seen around the world,” she told reporters, according to the AP news agency.
“We are considering it as a suicide because there was only one victim. But investigations will show if that was indeed the case.”
Earlier, the Supreme Court said in a statement that the building had been evacuated as a “precautionary measure” after explosions were heard. Justices had just finished hearing a plenary session and were quickly evacuated safely, it added.
The court is located in the Plaza de los Tres Poderes, across the square from the presidential palace. Local media reported that President Luiz Inácio Lula da Silva had left the area shortly before the blasts.
The explosions come just a week before Chinese President Xi Jinping is due to visit the capital, following a trip to a G20 summit in Rio de Janeiro.
Last year, the plaza was the scene of mass disorder, after supporters of ex-President Jair Bolsonaro ransacked the buildings in a bid to prevent his electoral defeat by President Lula.
