By Daniel Ramos

LA PAZ (Reuters) - Protesting Bolivian miners on Friday abandoned a roadblock where a day earlier they kidnapped a government deputy minister, who was later found beaten to death.

President Evo Morales called for three days of national mourning and declared Friday a day of "deep pain" for the country.

Deputy Interior Minister Rodolfo Illanes, 56, was beaten to death on Thursday after being taken hostage by miners who had blocked a major highway near Panduro, around 160 km (100 miles) from capital city La Paz. Officials said he died of blows to the head.

The brutal killing of a senior minister has shocked the country and the violent protests highlight the conundrum Morales has of keeping his increasingly divergent core support happy at a time when income istight.

The deputy minister had traveled to Panduro to negotiate with the miners on Thursday. His body was found early on Friday morning by the side of the highway that connects La Paz with the city of Oruro, wrapped in a blanket, said Edwin Blanco, the prosecutor in charge of the investigation.

"The cause of death was basically bleeding in the brain. Ribs were also broken," Blanco told reporters.

Illanes' assistant was also badly beaten and is in intensive care in a hospital in La Paz.

At least two miners were killed and 17 police injured earlier this week, authorities said, after they clashed when the protesters blocked the highway. On Friday the road was clear as they abandoned the blockade.

The miners - who belong to co-operatives digging for tin, zinc, silver