A Brazilian judge revoked on Thursday her own injunction blocking the Rio de Janeiro leg of the Live Earth global series of concerts after organizers secured approval from the police and met security concerns.

"The show is on again. The prosecutor's office asked the judge to reconsider and she revoked the suspension," said a spokeswoman for the Rio Justice Tribunal.

The prosecutor's office, which requested the initial injunction, had argued there were not enough police to safeguard Saturday's climate change awareness concert on Copacabana beach.

It said police officers would be busy with the Pan American Games that start on July 13 in the crime-plagued city.

But the municipal RioTur tourism authority, which is involved in the concert's organization, said it and other organizers obtained a police guarantee on Thursday that there would be adequate security at the event.

The court injunction triggered fears of a second cancellation in the Live Earth series.

Last month, Istanbul was dropped from the list of cities set to hold the concerts because of a lack of interest and security concerns. Ticket sales have been slow for most Live Earth shows and organizers had to change venues in Johannesburg in a bid to improve sales there.

A giant beach stage in front of Rio's plush Copacabana Palace hotel has already been erected. Organizers say they plan to use dozens of observation towers and platforms as well as police cameras in the security plan for the event.

Police have stepped up operations against drug gangs in Rio's slums in the run-up to the Pan America Games. Last week, they raided a slum on the city outskirts, killing about 20 people after a long siege of the area in which two dozen people had been killed and more than 60 wounded since May.

Eight cities are due to hold the concerts on Saturday, aiming to raise awareness about global warming with performances by stars including Madonna, Shakira and the Beastie Boys.

Performers including Lenny Kravitz, Pharrell Williams, Jorge Ben Jor and Macy Gray have been lined up to play on Copacabana to an expected audience of up to 1 million people in the only free, open-to-all event of the Live Earth series.

A cancellation would be embarrassing for city officials who hope the show and the games will showcase Rio's legendary charms instead of exposing its rampant crime.

Rio has one of the highest murder rates in the world, with a toll comparable to some war zones. At least 1,800 people were killed in the first four months of 2007 in the metropolitan area, official figures show.

Concerts are also due to take place in London, Sydney, Tokyo, Shanghai, Hamburg and East Rutherford, New Jersey.