A search is underway in the Brazilian state of Sao Paulo for a gang which broke into a police station, BBC reported.
They stole drugs and weapons, including submachine guns, and then blew up the building up before escaping.
No-one was injured in the explosion and police believe the attack may be linked to the arrest of a leading drugs trafficker in the area.
The local police chief has described what happened as an attack on the state.
While police in Brazil are used to dealing with violence even they seem taken aback by what they have described as a daring attack.
The gang arrived at the police station in the city of Botucatu in Sao Paulo state in the early hours of Monday morning and according to neighbours broke down the front door to get inside.
Among items they stole were at least 20 weapons including pistols, rifles, submachine guns and bulletproof jackets.
The police station which was used by officers investigating the drugs trade was empty at the time.
The gang took with them some cannabis and cocaine that was inside a safe before spreading petrol and setting off the explosion.
It is thought that dynamite may have been used to blow up the building, and such is the extent of the damage that at least part of the police station will have to be knocked down, once the investigation is complete.