Dozens killed as gangsters attack police in Sao Paulo

More than 50 people, including dozens of police officers, have been killed by heavily armed gangsters in the Sao Paulo region in an unprecedented weekend of violence in Brazil's most populous state.

An infamous criminal gang were thought to be behind a spate of over 100 attacks on police stations, patrol cars and bars frequented by off-duty officers over the weekend, with related uprisings breaking out in prisons across the state.

Sao Paulo has 144 jails, at least 57 of which were in open rebellion yesterday. On Saturday only 18 prisons were involved; within 24 hours the number had trebled, with inmates holding a total of more than 260 people hostage, the majority of them prison wardens. By last night, at least 36 policemen were among the dead and another 50 people, the majority police officers, had been injured.

The violence amounts to a declaration of war by the First Capital Command gang, or PCC, founded by prisoners at one of Sao Paulo's largest jails.

The uprisings were "the most vicious and deadliest attacks on public security forces that have ever taken place in Brazil," Enio Lucciola, a spokesman for the state's public safety department, said.

The PCC was "trying to undermine our authority and intimidate us ... when we have redoubled our efforts to destroy the organisation," he added.

The attacks apparently came in reprisal for the transfer of almost 700 prisoners, including many PCC leaders, to solitary confinement ­ a practice regularly employed by the authorities to break the links between them and the gangs on the streets outside. The move was apparently designed to thwart a co-ordinated revolt planned by the PCC at the weekend in several prisons in the state.

Instead, systemic violence erupted against the police, carried out by assailants who were armed with machine-guns and grenades. In one incident a home-made bomb was thrown into a police station; in another, a courthouse was attacked.

The gang members struck not only in the city and suburbs of Sao Paulo itself, but also in the coastal towns of Cubatao and Guaruja. In addition to those killed, at least 50 people were wounded, including 15 suspected gang members.

The PCC, which is one of the most powerful criminal organisations in Brazil, is active in drug and arms trafficking. It has also been responsible for many kidnappings, bank robberies and prison outbreaks and rebellions in recent years.

As the worst of the initial violence began to subside, police set up checkpoints in the low-income Sapopemba district of Sao Paulo on Saturday, stopping and searching vehicles for weapons. Brazilian TV showed pictures of bullet-riddled police cars and shattered glass at one police station that was attacked.

Originally rebellions broke out at 24 of the state's 144 prisons, but six of them were quickly put down.

The carnage is the latest in a series of attacks. During a 10-day period in November 2003, the PCC attacked more than 50 police stations, killing three officers and injuring a total of 12, in an apparent bid to to force authorities to improve conditions in the primitive, desperately overcrowded jails. Two years earlier, the PCC orchestrated a prison uprising that spread to 28 other jails across the state, causing the deaths of 19 inmates.