Brazil's environment agency, Ibama, has given the go-ahead for initial work to begin on a huge hydroelectric dam on a tributary of the Amazon River.
Ibama approved the clearing of forest at the planned site for the Belo Monte hydroelectric plant in the northern state of Para.
Licences still have to be granted for the building of the plant.
Contracts for the dam were signed last August after years of protests.
On Wednesday, Ibama gave approval for 238 hectares of land to be cleared. However, the BBC reports further legal challenges are likely.
The government says the Belo Monte dam is crucial for development and will create jobs.
It will be 6km long. Environmental groups say 500 sq km of land will be flooded.
Norte Energia, a consortium led by the state-owned Companhia Hidro Eletrica do Sao Francisco, was awarded the contract last year.
The 11,000-megawatt dam is expected to cost between $US11 - $US17 billion and provide electricity to 23 million homes.
The initial project was abandoned in the 1990s amid widespread protests both in Brazil and around the world.