A bus was set on fire Monday morning by armed men and another was shot at in the southern Brazilian state of Santa Catarina, which has been experiencing a wave of violent attacks in recent days, police said.

Police reinforcements made available by the state government to attempt to quell the attacks did not prevent attackers from setting a bus ablaze in the city of Navegantes or masked gunmen from opening fire on another in Itajai.

Nobody was hurt in either incident.

The Navegantes attack raises to 18 the number of public buses set on fire in the past five days by criminal groups, who have also burned trucks and private automobiles and have shot up police stations.

Since last Wednesday night there have been more than 40 attacks of this kind in Santa Catarina and authorities have arrested 20 suspects.

This is the second wave of attacks in three months in this state with another 60 similar attacks being registered in a seven-day period last November.

Besides increasing the presence of law enforcement personnel in the cities most heavily affected by the attacks, police are providing escorts for some buses as they ply their routes.

Authorities say the attacks are being staged in response to police operations against drug trafficking bands and more stringent treatment of inmates in prisons in the state. EFE