The kidnappings took place in the Chapare region of the Cochabamba department on Friday, according to Bolivia's Foreign Ministry.
Thus, the conflict escalates between supporters of the former ousted president Morales and the country's central government.
Already on Friday, reports emerged that about twenty soldiers had been taken hostage, but the number increased significantly on Saturday.
Weapons and ammunition have also been stolen in connection with attacks on three military installations.
Sources within Bolivia's military say that "irregular armed groups" are behind the kidnapping.
Morales was forced to leave power after attempting to be re-elected by changing Bolivia's constitution. He then left the country and has since come into conflict with the ruling faction within his old party.
Evo Morales was president from 2006 to 2019 and the first head of state in Bolivia to come from the indigenous Aymara people.
