“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.
“The Military Police robot is searching the body of the individual who carried out the attack, and a timer was identified, and it is possibly linked to other explosives,” said police spokesman Maj Raphael van der Broocke.
“Other explosives have already been identified around the body,” he added. “We need to be very careful to carry out this search and, if necessary, detonate these explosives at the site to prevent them from causing a chain reaction.”
Brasilia’s Deputy Governor Celina Leao told reporters the explosion had occurred after a man approached the entrance to the court and failed to gain entry. She recommended that 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.”
An eyewitness said she had seen a man waving at her before throwing explosives at the Supreme Court justice building.
“I was at the bus stop and this guy just waved hello and didn’t say anything else,” Lavana Costa told TV Globo.
“Then we heard the noise. I looked around at the noise and saw fire and smoke. The Supreme Court [STF] security guards came… He had already thrown something at the statue of justice.
“When the STF security guards were approaching, he threw something again. That’s when it blew up and he fell to the ground.”
Earlier, the Supreme Court announced that the building was evacuated as a precaution after explosions were heard. Justices had concluded a plenary session and were swiftly and safely evacuated, the statement noted.
The court sits in Praça dos Três Poderes, or Three Powers Plaza, directly across from the presidential offices. Local reports indicated that President Luiz Inácio Lula da Silva had departed the area shortly before the blasts occurred.
The explosions took place just a week before Chinese President Xi Jinping is set to visit Brasilia, following his attendance at the G20 summit in Rio de Janeiro.
This plaza was also the site of last year’s upheaval, where supporters of former President Jair Bolsonaro stormed the buildings in an attempt to prevent his electoral loss to President Lula.