Police surrounded the home of a man who shot and wounded three people early Thursday here in Brazil's largest city.
The shooter, identified as Fernando Gouveia, 32, suffers from schizophrenia, police said.
Around 30 police officers took up positions around the home in Sao Paulo's Aclimação neighborhood as authorities continued urging Gouveia to surrender.
Gouveia shot a judicial official, psychologist and nurse who came to his home Thursday morning to enforce a court order committing him to a psychiatric hospital, police said.
The three shooting victims were listed in stable condition at a nearby hospital, the municipal health department said.
Gouveia is alone in the home and poses no danger to anyone else, police spokesman Comte Marcelo Pignatari told reporters.
"We're not in a hurry," he said, speaking about three hours after the start of the siege. "The only condition is that he surrenders." EFE