Brazil has approved the construction of a massive hydroelectric dam in the Amazon rain forest — a project that has sparked criticism from environmentalists, indigenous activists and celebrities.

Brazil's environment agency Ibama issued the building license for the $11 billion dollar Belo Monte dam project on Wednesday. The dam is designed to produce about 11,000 megawatts of electricity.

It will be the world's third-largest hydroelectric energy producer after China's Three Gorges Dam and the Itaipu Dam, which straddles the border of Brazil and Paraguay.

Environmentalists and indigenous groups have said the dam will devastate wildlife in the area. British rock star Sting and American film director James Cameron have also expressed opposition to the project.

The consortium building the dam, Norte Energia, says it is expected to begin operating in 2015.

The project was originally conceived three decades ago and has been repeatedly delayed in recent years amid legal cases brought by environmentalists and native Indians.

In April, the Inter-American Commission on Human Rights urged Brazil to halt work on the dam until the government deals with concerns of the region's residents.

The commission, part of the Organization of American States, called on Brazil to take protective measures for the indigenous peoples who live in the area. The commission also called on the government to give the groups access to environmental impact reports.

Brazil's Foreign Ministry described the request as unjustified.