BOGOTA, Colombia (CNN) -- Colombian President Alvaro Uribe admitted Wednesday that police fired on Indian demonstrators despite a government pledge that security forces would not do so.
Uribe had earlier denied accusations that security forces fired at demonstrators during protests by thousands of Indians.
"The police did fire," Uribe said at a news conference Wednesday.
He made his remarks after CNN obtained and aired a videotape that shows police at La Maria Indian reservation.
The video shows a man in an olive green uniform and ski mask raise an M-16 assault rifle, standard issue for some Colombian police units, and fire three shots, though the target is unclear. Watch as a uniformed man apparently raises a rifle and fires it »
The incident happened last Thursday in southwestern Colombia, where thousands of Indians have been protesting since October 10 for greater land rights and against free-market capitalism. They are marching toward Colombia's second largest city, Cali, to demand more land, better education and health care and protection from corporations encroaching on their land.
The patrolman who fired, Uribe said, was being attacked with explosives. His supervisors did not know he fired, the president said.
"A television channel has shown a video that shows a member of the public forces firing," Uribe said. "That makes it look like the president of the republic has lied to the country and that affects democratic security.
"We need all the confidence of Colombians when it comes to democratic security and that does not allow the president of the republic to lie."
At least four protesters have been killed, including two Tuesday, and at least 130 have been injured during protests in the last two weeks, Indian leaders said. Medics said they have treated scores for gunshot and shrapnel wounds.
Protest leaders say security forces have fired on the Indians, but authorities have denied that. The government has said that some of the Indians who died were shot by other demonstrators in an effort to stir emotions in the crowd.
Demonstrators have blockaded roads that include the Pan-American highway, a main trade route in South America. Some have hurled stones from sling shots and thrown Molotov cocktails in clashes with riot police; authorities say other demonstrators have flung homemade explosives at security forces.
As many as 70 security force members, mainly riot police, have been hurt, the government has said.
The Indians who were killed died as a result of their own explosives and not police bullets, Uribe said.
"I worry when I see all these videos on international TV that don't show that this country has respected diversity," he said. "The government respects social protest. What the government doesn't tolerate is violence."