The police in Brazil reported an explosion in front of the Supreme Court building in the country's capital, the Associated Press reported, quoted by BTA.
Photos published in local media show a body on the ground in front of the courthouse.
A police statement said an object exploded outside the court, without giving further details.
An employee of the Supreme Court said he heard two explosions, which caused the building to be evacuated. He said the man, who was lying on the ground outside the court, appeared to be dead.
The fire department later confirmed the death of one person, but did not release his identity.
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 blasts.