Brazil's President Luiz Inácio Lula da Silva has vowed to punish supporters of the country's ex-leader, Jair Bolsonaro, after they stormed Congress.
Supporters of the ousted far-right leader also stormed the Supreme Court and surrounded the presidential palace.
But police regained control of the buildings in the capital Brasilia on Sunday evening after hours of clashes.
Arriving in the city, Lula toured the Supreme Court building to see the damage for himself.
Brasilia's Civil Police said that 300 people have been arrested.
The city's governor, Ibaneis Rocha, has been removed from his post for 90 days by the Supreme Court.
Justice Alexandre de Moraes accused him of failing to prevent the riot and of being "painfully silent" in the face of the attack. Mr Rocha has apologised for Sunday's events.
Pro-democracy rallies are being called by leftist leaders and groups across Brazil.