A notorious criminal gang unleashed a second wave of attacks against police, bringing to at least 52 the number of people killed in what one official called the deadliest assault of its kind in Brazil's history.
Sao Paulo state government officials reported at least 100 separate attacks on Friday, Saturday and Sunday that killed at least 35 police officers, the girlfriend of one of them, two passers-by and 14 suspected gang members.
On Sunday, dozens of new prison rebellions also broke out, with 41 uprisings under way across Sao Paulo state in the afternoon. Inmates were holding more than 229 prison guards hostage.
Late Sunday evening, the Folha de Sao Paulo newspaper's Web site reported the death toll had risen to 55 and that at least 10 public buses had been burned by bandits in the city of Sao Paulo.
TV images showed the buses engulfed in flames, while Folha Online said passengers were ordered out of the vehicles before bandits set them ablaze.
Enio Lucciola, spokesman for the Sao Paulo State Public Safety Department, said the attacks and prison rebellions, planned by the First Capital Command, known by its Portuguese initials PCC, "were the most vicious and deadliest attacks on public security forces that have ever taken place in Brazil."
The rebellious inmates, however, have not made any demands nor have they harmed any of their hostages, said Jorge de Souza, a press spokesman of the Sao Paulo Prison Affairs Department, reports the AP.