VILLARICA, Colombia (CNN) -- Two men were shot to death Tuesday in a clash with riot police amid a burgeoning Indian protest in southwestern Colombia.
The men were shot in the head and back as they sought to join thousands of Indians marching on Colombia's second-largest city, Cali.
Other demonstrators said government security forces fired on the men, but Colombian authorities denied the allegation. Police claim protesters attacked them with homemade explosives.
Tuesday's violence stirred resentment among Indians.
"We went out there today to reject the government, and they open fire on us," one protester said.
Col. Jorge Enrique Cartagena, national chief of Colombia's riot police, said someone in the crowd of demonstrators killed one of the two men.
"We think he was shot from within the crowd, and they're doing that to whip up anger," he said.
The Indians have said that security forces have been shooting at them with rifles and canisters packed with shrapnel.
Colombia President Alvaro Uribe has denied that police and army forces have been using lethal force against demonstrators, but medics said they have treated scores of Indians injured by bullets and shrapnel.
Protesters have blockaded the Pan-American highway, fired slingshots and hurled rocks and Molotov cocktails in periodic clashes with riot police. Authorities said they have fought back with tear gas, rocks and batons.
Demonstrators want the government to set aside more land for Colombia's 1.3 million Indians and to provide more money for better education and health care. They also would like the government to prevent corporations and multi-national companies from encroaching on their land.
So far, four protesters have been killed since demonstrations began October 10. At least 130 more have been injured. The government says as many as 70 security force members, mainly riot police, have also been hurt.