Some forty people, mostly foreign tourists, were held overnight Wednesday by indigenous Peruvians protesting the halt in construction of a highway through an area known for its protected natural areas and gold mining.

The tourists, released Thursday, had been traveling by boat to the Manu National Park reserve in the country's Madre de Dios region when they were intercepted by some 200 protesters, authorities said.

Juan Jose Salas, a guide who was taken along with the tourists, said the group of German, British and American travelers had little food or water and had struggled in the intense Amazonian heat.

Authorities, who reached an agreement with the indigenous group Thursday, said some of the tourists showed signs of dehydration but that they were not mistreated by the protesters.

"They will spend the night in a hotel and will be given first aid and food. Tomorrow, they plan to return to their countries of origin," Pedro Gamboa, head of the National Protected Natural Area Service (SERNANP), told Canal N TV.

"We have made it clear (to the protesters) that what they did was a crime," and that they will have to take a different route in pressing for the highway.

The protesters, from the indigenous communities Nativa Diamante, Isla de los Valles and Boca Manu, had been calling on the government to complete the construction of the road, which would go through a protected reserve.

SERNANP had stopped the construction, citing the lack of an environment impact assessment and fears the new road would lead to increased deforestation and illegal mining in the area, where gold mining is a leading industry.