A man killed himself while detonating explosives after trying to enter Brazil’s Supreme Court, authorities said Wednesday, in an attack on the political heart of the country that prompted the evacuation of court staff and legislators in the capital Brasilia.

The blasts come five days before the G20 heads of state meet in Rio de Janeiro, followed by a state visit to the capital Brasilia by Chinese President Xi Jinping.

The authorities were treating the blasts in Brasília, the capital, as the work of a lone bomber, who was believed to have been the person killed.