At least 81 people have been killed since an offensive was launched Friday night by organized crime groups in Brazil's commercial capital, Sao Paulo, and outlying regions of Sao Paulo state.
President Luiz Inacio Lula da Silva sent Justice Minister Marcio Thomaz Bastos to Sao Paulo, who said about 4,000 members of the armed forces stood ready to intervene and help contain the violence.
An estimated 150 attacks took place within a 40-hour period over the weekend against police stations and patrol vehicles, military facilities and prison outposts.
But the drug gangs shifted tactics Sunday night and into Monday, extending their offensive beyond Sao Paulo state, setting about 90 buses on fire and attacking 11 banks and two subway stations with molotov cocktails and sporadic gunfire.
Sao Paulo's second largest airport, Congonhas, had to be closed Monday after a bomb threat.
'This is like war, a nightmare,' said a resident living next to a bank attacked in the Vila-Olimpia quarter of Sao Paulo.
The drug gangs were also blamed for uprisings by prisoners in at least 60 correctional facilities. Around 120 hostages were still being held Monday night at 25 prisons in Sao Paulo state.
Among the dead during the violence since Friday at police stations, jails and other sites were 39 police officers and prison guards, four civilian bystanders and 38 suspected gang members. Another 60 people have been wounded, and 20 men have been arrested.
Police in Sao Paulo city were maintaining numerous roadblocks since Saturday, and key buildings such as police headquarters were under heavy guard.
Authorities believed that the coordinated mayhem was retaliation by Brazilian gangsters to the relocation against their will of about 740 inmates in the preceding days. Among the forced transfers were at least eight high-ranking gang bosses who were placed in solitary confinement.
One infamous gang, known as Primeiro Comando da Capital (PCC) or the First Capital Command, was suspected of coordinating many of the attacks and prison revolts. The group is believed to be controlled largely from inside the penitentiary system. Its purported leader, Marcos Willians Herba Camacho, or 'Marcola', was believed to be among the prisoners transferred.
Sao Paulo state Governor Claudio Lembo had requested federal help to deal with the violence during an emergency meeting of the heads of Brazilian security agencies on Sunday, but said he would not bow to organized crime.
Saulo de Castro Abreu Filho, security minister for Sao Paulo state, called the uprising an 'act of desperation.'
'Such actions by criminals will never be successful,' he said.
