Police in Bolivia forcibly broke up a march by hundreds of indigenous people angry over a controversial plan to build a highway through a rainforest reserve, drawing criticism from the UN.Several people were injured when police fired tear gas at demonstrators camped out near the northeastern village of Yucumo, whose residents mainly back President Evo Morales and who had set up a barricade to block the march. An AFP journalist saw several activists with superficial face wounds taken away by dozens of police officers, who were loading the marchers into buses to take them to a nearby city. Local police chief Oscar Munoz said two people had been injured and were being treated by doctors, but that their injuries were \"nothing serious.\" He added that some police were also injured in the melee.\"No bullets were fired, (only) some tear gas was used,\" he said. Police -- who also dispersed pro-government demonstrators in Yucumo -- pulled several protesters out of the heavy brush in the area, carting them off in handcuffs. Munoz said the demonstrators were not under arrest but would be taken back to their hometowns. But buses were blocked in a nearby town early Monday by residents angry about the police action. Indigenous activists from Bolivia\'s Amazon basin region left the northern city of Trinidad in mid-August in a bid to march on the capital La Paz to protest the highway plan. The road would run through a nature preserve that is the ancestral homeland of 50,000 natives from three different Amazonian groups, who have lived largely in isolation for centuries.The leftist Morales, the country\'s first elected indigenous president, favors the road project, arguing it is needed for development. But Amazon natives fear that landless Andean Quechua and Aymara people -- Bolivia\'s main indigenous groups -- will flood into the area and colonize the region. After more than a month of hiking from the Amazon rain forest, the protesters arrived just outside Yucumo on Saturday after breaking through a police barricade by forcing the country\'s foreign minister to march with them. The police action came after Morales, attempting to defuse tensions, said Sunday that a referendum would be held to determine whether the road project should go ahead. \"We are going to ask people (in Cochabamba and Beni departments) in a referendum,\" Morales said. \"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.\" It was not immediately clear how soon the vote would be held. The United Nations and rights groups criticized the police action. \"The most important thing for us is that they stop the violence as soon as possible,\" the UN envoy in Bolivia, Yoriko Yasukawa, said, reminding authorities that it was their responsibility to \"protect the people.\" Veteran human rights activist Maria Carvajal told AFP that police had surged into the demonstrators\' camp with \"extreme violence,\" adding: \"I could not believe what was happening.\"Bolivia is South America\'s only mostly indigenous nation.