The issue has pitted indigenous people from steamy Amazon basin lowlands who oppose the project, against Morales, who backs it, and migrants mostly belonging to the country's two main Andean highland indigenous groups. "We are going to ask people in (Cochabamba and Beni departments) in a referendum. If they say yes, a study will be done to see where the best route for that road is, the most direct... and with the least environmental impact," Morales said. The announcement was made at a protest by farmers in San Antonio of the 16 tribes of the Isiboro Secure National Park. It was not immediately clear how soon the vote would be held. Amazon basin indigenous activists left the northern city of Trinidad in mid-August in hopes to march on the capital La Paz to protest the plan; it had called for building a highway through a nature preserve that is the ancestral homeland of 50,000 natives from three different Amazonian groups. After more than a month of hiking from the Amazon rain forest, the protesters arrived just outside Yucumo Saturday, a small town northeast of La Paz that is largely supportive of the government, after breaking through a police barricade. Police said they intervened in Yucumo to prevent confrontation between the marching protesters, and another set of pro-government demonstrators just 300 meters (1,000 feet) away who had set up a barricade. Bolivian media said several people had been injured, but an official toll was not immediately available. The United Nations' delegate in Bolivia, Yoriko Yasukawa, said: "the most important thing for us is that they stop the violence as soon as possible. And to remind the authorities that it is their responsibility to stop violence and protect the people." Morales separately pledged to push any illegal settlers out of the national park. While Morales, a leftist, is an indigenous leader himself, some among the Amazon basin indigenous groups fear he might not be duly protecting their lands from "incursion" by members of the main ethnic Aymara and Quechua groups. Morales is the first elected indigenous president of Bolivia, which is South America's only majority indigenous country.