Hundreds of indigenous demonstrators in Bolivia's Amazon basin region forced the country's foreign minister to join their protest march, using him to break through a police blockade.
Protesters, who are not from Bolivia's two main groups of natives, oppose plans to build a highway through a rainforest reserve which they fear will bring migrants into the steamy lowlands they have called home for centuries.
The demonstrators have been walking for weeks, and are headed for the capital La Paz.
They forced Foreign Minister David Choquehuanca -- who was trying to negotiate with the protesters -- to march with them past riot officers into an area where rival Andean highland indigenous people had settled.
"They made me march. They made me do it," Choquehuanca, visibly tired after walking for about four hours, told local media.
He was released near Yucumo, 10 kilometers (six miles) from the blockade near Chaparina.
"The situation is difficult," Choquehuanca said upon returning to La Paz, referring to tensions between protesters and other indigenous people who support President Evo Morales.
Protest leader Adolfo Chavez told local radio that native women were clutching Choquehuanca's arms and had forced him to join the march, using him as a sort of "human shield."
Another official was also forced to take part in the march, an AFP journalist witnessed.
About 1,000 protesters headed toward Yucumo from Chaparina, another town 323 kilometers northeast of the capital La Paz where highland indigenous people who support Morales have settled.
Dozens of Morales supporters in Yucumo burnt tires and took refuge behind mounds of dirt and tree trunks in hopes of preventing the protesters from continuing their march.
Four police officers were injured in scuffles with protesters on Saturday, including two who were struck in the face by arrows held by demonstrators, Interior Minister Sacha Llorenti said late Saturday.
Demonstrators were apparently carrying spears and arrows to hunt for food during their protest march -- which they say will take them to La Paz -- and to protect themselves.
Choquehuanca had been attempting to mediate between the groups, which he has said could engage in ethnic slaughter on the scale of Rwanda's bloody 1994 genocide between Hutus and Tutsis.
But they have flatly rejected his efforts.
Llorenti said the foreign minister had been "kidnapped" and announced plans to file a complaint against the natives Monday at the Inter-American Commission on Human Rights.
Simeon Jaliri, a leader of the confederation of farm workers representing Quechua and Aymara people -- said they had declared a state of emergency after what happened to Choquehuanca.
"We are prepared to mobilize," he warned.
Bolivia is South America's only mostly indigenous nation. The Socialist president Morales is an indigenous leader himself, and favors the road project, arguing it is needed for development.
The planned highway would run through an Amazon forest natural reserve where natives have lived largely in isolation for centuries.
Amazon natives fear that landless Andean Quechua and Aymara people -- Bolivia's main indigenous groups -- will flood into the area and colonize the region.