A man who failed in an attempt to break into Brazil's Supreme Court killed himself in explosions outside the building Wednesday, authorities said. 

Authorities evacuated the Supreme Court premises in Brasilia following two loud bangs heard within 20 seconds of each other.

A police officer told local television the dead man found in the square had an explosive device on him.

Celina Leao, the lieutenant governor of Brazil's federal district, said police suspect the man who died caused the explosions.

"It could have been a lone wolf, like others we've seen around the world," Leao said in a news conference. "We are considering it as a suicide because there was only one victim. But investigations will show if that was indeed the case."

Explosion in trunk of parked car

The first explosion occurred in the trunk of a parked vehicle in a car park next to the court building.

"His first action was to explode the car," Leao said. "Then he approached the Supreme Court and tried to get in the building. He failed and then there were the other explosions."

The court's justices safely left the building after the incident, which took place at about 7:30 p.m. local time (2230 UTC), shortly after Wednesday's session finished. 

Police searched the area for other explosive devices, and the country's solicitor general called the explosions on social media an "attack."

The Brazilian Chamber of Deputies, the lower house of the country's National Congress, suspended its session following the explosions near the Supreme Court.

Police treat attack as 'terrorist act'

The Federal Police is investigating the explosions as an act of terrorism, its director, Andrei Passos Rodrigues, said on Thursday.  The blasts could also have been a violent attempt to overthrow the "democratic rule of law," he added.

"As much as this was an individual, behind him there is all of this discourse that leads someone to commit this," Rodrigues said. "These actions are not isolated actions."

The perpetrator was identified as Francisco Wanderley Luiz, a 59-year-old member of former President Jair Bolsonaro's far-right Liberal Party (PL).

Meanwhile, a Brazilian Supreme Court judge said the explosion outside the court in Brasilia was the result of frequent far-right attacks and hate speech targeting the country's institutions.

"It grew under the guise of a criminal use of freedom of speech. To offend, threaten, coerce," Justice Alexandre de Moraes said.

Brazil's Supreme Court a target for threats

The incident occurred in Brasilia's Three Powers Plaza, where Brazil's main government buildings are located.

The Supreme Court stands across the square from the presidential palace.

A spokesman for President Luiz Inacio Lula da Silva said the 79-year-old leader was not in the neighboring presidential palace at the time of the blast.

In recent years, the Supreme Court has become a target for threats from far-right groups and supporters of former President Jair Bolsonaro due to its efforts to curb the spread of misinformation.

The blasts occurred just five days before global leaders from the Group of 20 major economies meet in Rio de Janeiro, highlighting major security concerns.

Chinese President Xi Jinping is also scheduled to visit Brasilia in a few days.

dh,ss/sms,ab (AP, Reuters, AFP)