A group of independent miners linked to the death of a deputy minister are part of a "political conspiracy," said President Evo Morales on Friday.
Announcing three days of mourning, Morales said the striking miners had been manipulated by opposition forces when they launched protests that resulted in the death of Deputy Interior Minister Rodolfo Illanes on Thursday.
"He was beaten to death. Deputy Minister Illanes was murdered in a cowardly and brutal fashion," Interior Minister Carlos Romero said.
Prosecutors said that Illanes, 55, died after being struck multiple times. His bodyguard was also hospitalized with a head injury.
More than 100 miners have been taken into custody due to the incident, Defence Minister Reymi Ferreira said.
Illanes' death came during a visit to a site where miners have gone on strike to protest government policy. As he arrived, police and miners began fighting in the town of Panduro, 165 kilometres south-east of La Paz.
Romero said Illanes had been kidnapped by miners following an attempt to initiate talks with them at a roadblock. After he was taken hostage, he called government colleagues three times to provide updates. He said he was being held by miners who wanted the police to fall back and who demanded a dialogue with the government, according to the newspaper El Deber.
The government did try to set up talks, and a group of miners travelled to La Paz. But, as that was happening, fighting escalated in Panduro. One 26-year-old miner died of a gunshot wound. Security forces also launched an effort to free Illanes.
Two miners died in related violence on Wednesday.
Demonstrators blamed the police for the deaths, but the government accused the miners of carrying arms and said police had never carried weapons in their attempts to disperse the demonstrations.
Miners represented by independently organized cooperatives have been using street blockades to protest a law that would allow its members to join trade unions. The cooperatives say they are against the influence of the unions.
The national federation of mining cooperatives (Fencomin), representing some 10,000 miners from 900 cooperatives, rejects any trade union influence on Bolivia's mining sector.
They also want foreigners to be able to invest in the cooperatives and a loosening of environmental laws.