Authorities in Brazil say they have killed at least 18 more suspected gangsters in Sao Paulo, where police have been trying to quell a wave of violence.

Local media say the killings occurred Wednesday. Few other details were given.

The violence in Sao Paulo began on Friday when members of the First Capital Command gang, fired on police stations and launched rebellions at several prisons. Order was restored in at least 70 facilities after prison officials negotiated the release of about 200 hostages late Monday.

Police say the gang ordered the attacks to protest the transfer of several imprisoned leaders to maximum security facilities.

More than 130 people, including at least 40 police officers, have been killed in the unrest.

Some information for this report was provided by AFP, AP and Reuters.