Security fears intensified in Brazil’s capital on Wednesday evening after a man set off two bomb explosions near the Supreme Court, killing himself just days before the city is set to welcome world leaders for the G20 Summit and a state visit from Chinese President Xi Jinping.

The first blast occurred in a parking lot close to the Supreme Court, with a second explosion following near the court’s entrance, where the man’s body was later found. Preliminary investigations suggest that the individual had attempted to enter the Supreme Court before detonating explosives on himself, according to Federal District Vice Governor Celina Leao. She noted that the man appeared to have owned a nearby car, which also exploded, blowing open the vehicle’s trunk.

Vice Governor Leao stated that authorities are treating the incident as potentially the act of a “lone wolf” attacker but cautioned that no final conclusion had been reached. Police are currently working to identify the man while carefully inspecting for possible additional explosives on his body.

The explosions took place in Brasilia’s iconic Plaza of the Three Powers, a square that houses Brazil's three main federal government institutions. This same area was stormed in January of last year by supporters of former President Jair Bolsonaro following his electoral defeat.

Police swiftly deployed a bomb squad, including an explosive disposal robot, to the scene to secure the area. Supreme Court justices, who had just adjourned a plenary session, were quickly and safely evacuated. President Luiz Inácio Lula da Silva, who had left the executive palace shortly before the explosions, was unharmed.

With G20 heads of state set to gather in Rio de Janeiro and President Xi scheduled to visit Brasilia next week, Wednesday’s events have heightened security concerns in advance of these high-profile events.