Brazilian President Luiz Inacio Lula da Silva says about 1,500 people are in custody for suspected involvement in Sunday's storming of the Congress and other buildings in the capital, Brasilia.

About 4,000 people thought to be the supporters of former President Jair Bolsonaro broke windows and destroyed equipment and documents in government buildings on Sunday. Security troops have removed the intruders and cleanup work has begun at affected locations.

President Lula stressed on Monday that he will make an all-out effort to find out who was behind the incident. He said he will thoroughly investigate what happened, as well as who provided financial support.

Lula supporters demonstrated across the country late Monday afternoon. About 1,000 people took part in a rally in Brasilia, calling for Bolsonaro to be jailed.

One participant said she's very sad about what happened, so she joined the demonstration to safeguard democracy. She says she feels as though the divide within country is deepening.

Meanwhile, Bolsonaro's wife has disclosed that her husband has been hospitalized in the US state of Florida in poor health.