Brazilian President Jair Bolsonaro said on Friday the country could open a vast reserve in the Amazon rainforest to mining, a move that his predecessor attempted before backtracking due to an international outcry by environmentalists.

The National Reserve of Copper and Associates (Renca) occupies roughly 17,800 square miles (46,100 square km), an area slightly larger than Denmark, that is thought to be rich in gold, copper, iron ore and other minerals.

"Let's talk about Renca. Renca is ours," Bolsonaro said at a televised event in Amapa state, home to part of the reserve.