Gunmen attack Rio state palace

Authorities have stepped up security at the palace

Gunmen have sprayed machine-gun fire into Rio de Janeiro's state government palace in the latest in a series of attacks which have marred the run-up to the country's elections.

Drug lord control much of Brazil's slums

No-one was injured in that attack, but unknown assailants later threw a hand grenade into a popular shopping centre and opened fire on a downtown police station, reportedly killing at least one police officer.

Authorities say they fear it may be another show of force by local drug barons in the run-up to elections due to be held 27 October.

The city's governor, Benedita de Silva, said the incidents may be a reaction to the foiling of a prison break late on Tuesday, in which gangs armed by drug lords attempted to invade the Bangu III prison, causing a riot in the process.

"The bandits had a plan," Governor da Silva told French news agency AFP.

"While one group created commotion in the city to attract attention, the inmates would attempt a breakout."

She has since asked the federal government to deploy soldiers in the state to guarantee safety during the elections.

"We will not be intimidated," she added.

City shutdown

Brazilian authorities said the attempted prison outbreak was prevented when police were tipped off about a drug gang - possibly the Comando Vermelho or Red Command - which planned to rescue imprisoned drug lord Isaias do Borel, the Associated Press news agency reported.

Lula: Ahead in most recent polls

Earlier this month drug barons brought much of the city to a standstill - shutting down hundreds of shops across the city, including businesses around the fashionable Copacabana and Ipanema beaches.

Police said at the time they were baffled by the shutdown.

Such orders have been issued by gangs in the past, but usually only to mark the death of a gang leader, and never before to the fashionable South Zone with its beaches.

Elections imminent

Drug gangs such as the Red Command have long controlled Rio's many shantytowns, or favelas, however recent incidents indicate that they, and other gangs, have become more audacious in their attempts to assert control over the city.

The violence also comes as Brazil prepares for a run-off election after voting on 6 October failed to produce a candidate with the 50% of the vote required to fill the position.

Recent polls indicated that opposition candidate Luiz Inacio Lula da Silva, known as Lula, holds 66% of the vote compared to the ruling party candidate Jose Serra, who commands just 35% of the vote, the Associated Press news agency reported.