Two rival marches have been held over the Ecuadorian government’s plans to develop large-scale mining in the Amazon region.
Indigenous groups from that part of the country arrived in the capital on Thursday to voice their anger after marching for two weeks.
They say it will pollute their homelands and displace thousands of people.
Supporters of President Rafael Correa held a counter-demonstration to back his plans to open up the mining industry to more foreign investment.
Correa says he will spend the proceeds on welfare and development projects.
“Our opponents say we must choose between clean water or mineral resources, as if we cannot have both, comrades,” he said.
Earlier this month, the government agreed a one billion euro deal with a Chinese mining firm to develop a new copper mine near El Pangui.
Correa sees the plans as essential if Ecuador’s economy is to become less dependent on oil exports.