Sao Paulo, Brazil ? Police struck back Tuesday at gangs that rampaged through South America’s largest city, killing 33 suspected gang members in less than 24 hours and frisking motorists at roadblocks while reporting only one death of their own.

At least 133 people – including 40 police officers – have been killed since Friday night, when a prison transfer of gang leaders sparked attacks on police stations, courts, city buses and other symbols of government authority.

But while gang attacks fell off sharply Tuesday in Sao Paulo, the death toll within their ranks rose dramatically.

Officers “acted within the law, but that doesn’t mean we have to let them humiliate us,” Marco Antonio Desgualdo, a top Sao Paulo state law enforcement official, told reporters. He did not give specifics about the killings.