Volkswacht Bodensee - Northeast Brazil sees more fierce gang violence

Media reports carried images of public buses and buildings in flames in nine cities -- including state capital Natal -- in the northeastern Rio Grande do Norte state.

The unrest, which began late Monday, was orchestrated by imprisoned gang leaders as a protest against jail conditions and new regulations cracking down on criminal activity within the state penal system.

In Natal, a garbage collection center, a supermarket and a gas station were all set ablaze, the G1 news site said.

"Never in my life have I seen something like this going on. We left for work... and we came across this. It is very sad," Reinaldo Silva, a mason in Natal, told AFP.

Authorities dispatched an additional 220 federal police to the state but reinforcements may climb as high as 800 in coming days, Justice and Security Minister Flavio Dino told CNN.

At least 28 urban areas in the state have been hit by the disturbances this week, authorities said.

Local media have carried footage of vehicles in flames, and of police cruisers, businesses and government buildings riddled with bullets.

Leftist President Luiz Inacio Lula da Silva hasn't spoken public about the disorder.

At least two people were killed in clashes with police earlier in the week, and 67 people have been arrested, public security sources in the state told AFP.

I.Meyer--BTB