Inmates of a crowded suburban Sao Paulo prison killed a guard during a riot Monday and were holding three more guards hostage, authorities said.
Prisoners at Sorocaba Prison, armed with knives and sticks and demanding better conditions, locked up four guards in a visitors' room and beat one of them to death, said a spokesman at Sao Paulo's public-security office.
"An intermediary is now on his way to hear their demands," the spokesman said. "Normally, they are things like transfer to another prison due to overcrowding."
Local radio said that among other demands, inmates wanted to be allowed to sunbathe on the prison patio. The jail holds more than 500 prisoners.