A Brazilian judge has suspended work on a massive hydroelectric dam in the Amazon jungle, saying it would harm fishing activities on the Xingu River.
Brazil's government, which strongly backs the $11-billion, 11,000-megawatt project as necessary to fuel the country's growing economy, said it planned to appeal the ruling.
Judge Carlos Eduardo Martins said he halted construction of the controversial Belo Monte dam because it would harm fishing by indigenous communities on the Xingu River in Para state. His ruling was posted on a court website on Thursday.
The Norte Energia consortium that is building the dam said it had not been informed of the ruling.
The Belo Monte dam would be the world's third-largest hydroelectric energy producer behind China's Three Gorges dam and the Itaipu dam, which straddles the border of Brazil and Paraguay.
The government has said it will be a source of clean, renewable energy, and damage to the environment would be minimized. The Valor Online website quoted the executive secretary of the Mines and Energy Ministry, Marcio Zimmermann, as saying the government and the consortium are "taking the steps necessary to appeal the ruling."
But environmentalists and indigenous groups say the dam would devastate wildlife and the livelihoods of 40,000 people who live in the area to be flooded.
Celebrities including British rock star Sting, film director James Cameron and actress Sigourney Weaver have joined activists in lobbying against the dam.
When Cameron participated in protests against the project in Brazil last year, he compared the anti-dam struggle by indigenous people to the plot of his film "Avatar," which depicts a natives of a planet fighting to protect their homeland from plans to extract its resources.
Last month, President Dilma Rousseff said the dam will not harm indigenous communities living in the region.
This is not the first time a judge has ordered construction of the dam stopped.
In February, a federal judge ordered work suspended claiming that Brazil's environmental agency had erred when it approved work to begin.
Judge Ronaldo Desterro said 29 environmental conditions such as the recovery of degraded areas and measures to guarantee the navigability of rivers had not been met.
But one week later Judge Olindo Menezes of a higher federal court overturned the suspension, saying there was no need for all the conditions to be met before construction begins.