Elite police commando units fanned out across the streets of southern Brazil on Saturday, in a bid to contain a wave of violent attacks over the past two weeks.
The attacks -- allegedly ordered by criminal gangs from within Brazil's prisons -- have seen buses and private passenger cars torched and police fired upon in some 30 towns and cities in Santa Catarina state since January 30.
"With the support of the national police force, we have launched Operation Secure Santa Catarina," state military police spokesman Joao Carlos Neves said.
Reinforcements began arriving on Friday from elite federal police units to help contain the violence that has overrun the region. Now more than ever, security is a high-profile issue as Brazil gears up to host 2014 World Cup matches and the 2016 Summer Olympics in Rio.
Authorities said police have already made scores of arrests, and said prison officials also transferred some inmates blamed for the mayhem to other facilities.
The prison-based crime rings reportedly unleashed the wave of violence to pressure authorities to provide better living conditions for inmates.
Justice Minister Jose Eduardo Cardozo, who headed to Florianopolis to supervise the operation, told reporters that at least four lawyers collaborating with the gangs were also detained.
Press reports have blamed the First Group of the Capital, a gang similar to a Sao Paulo-based prison syndicate known as the PCC, or First Command of the Capital.
The PCC was allegedly involved in various attacks and clashes with police that claimed more than 300 lives in and around Sao Paulo between October and early December.
Santa Catarina, a state with some 6.2 million inhabitants, also witnessed an outbreak of criminal violence in November.
Much of the violence has been carried out in Florianopolis, a university and resort city that serves as the state's capital.