Hundreds of Indians and peasants are occupying a construction site in a bid to stop the controversial Belo Monte hydroelectric project in Brazil's Amazon region, a Catholic organization said Thursday.

Around 600 people, including members of 21 different Indian nations, fishermen and other residents along the banks of the Xingu River, were taking part in the protest, the Indigenous Missionary Council said.

A source with Norte Energia, the consortium building the dam, told Efe the initial occupation involved some 100 protesters.

Late Thursday, a municipal judge in Altamira, the town nearest the construction site, issued an injunction ordering the protesters to end the occupation.

Judge Cristina Collyer Damasio granted a motion from Norte Energia and threatened to fine each of the protesters 500 reais ($292) a day if they ignored her order.

The protesters' chief demand is for the Brazilian government to send representatives to negotiate with local residents on ending the Belo Monte project.

The dam in the northern state of Para is scheduled to come online in 2015 as the world's third-largest hydroelectric complex after China's Three Gorges and Itaipu, jointly operated by Brazil and Paraguay.

A dozen suits have been filed in the Brazilian courts to block the project and the Inter-American Human Rights Commission held a hearing this week in Washington on demands to halt the dam.

Brazil refused to send a representative to the session at the headquarters of the Organization of American States, prompting dam opponents to accuse President Dilma Rousseff's government of maintaining a "shameful attitude" toward the indigenous peoples.

First proposed in the 1970s by the military regime then ruling Brazil, the Belo Monte project was revived by the 2003-2011 administration of Luiz Inacio Lula da Silva.

Rousseff played in a key role in promoting the dam when she was Lula's chief of staff, touting it as one of the Amazon region's most important energy initiatives.

The price tag for the dam, which will have a generating capacity of 11.2 GW when the Xingu River's water level rises during the rainy season, has been estimated at $10.6 billion.

The Brazilian government defends Belo Monte as necessary to ensure the country has sufficient electricity supplies and denies that indigenous lands will be flooded, but environmentalists say the project will be inefficient and have a devastating impact.