Bolivian security forces clashed with supporters of former President Evo Morales, leaving at least five people dead and dozens more injured.
A doctor in the central city of Sacaba said most of those killed and injured had bullet wounds.
However, no deaths were reported by the Bolivian authorities.
Morales, who said he was forced to resign last Sunday amid protests following the disputed presidential election, has fled to Mexico.
He later took to Twitter to broadcast that the massacre had occurred and to describe Bolivia’s interim government as a dictatorship.


Swiss prosecutors summon owners of ski resort bar after deadly blaze
Trump cancels second wave of attacks on Venezuela after cooperation
Widespread power cuts, travel disrupted as Storm Goretti hammers northern Europe
At least one killed, dozens missing in landfill collapse in central Philippines
Trump says he will meet with Venezuela's Machado next week