Tear gas wafted through Cochabamba streets as security forces detained protesters in the latest manifestation of unrest plaguing the country led by interim president Jeanine Anez.
Anez, 52, a former opposition senator, assumed the presidency after Morales and his vice president resigned at the "suggestion" of the military, followed by three others in the line of succession. Mexico has given Morales asylum.
But Anez has faced a wave of protests led by Morales supporters who say she was installed in a coup and that her presidency threatens the gains made for the non-white majority in Bolivia during Morales' 14 years in office.
Police fired tear gas at the protesters in Bolivia's coca-growing highlands to keep them from entering the city of Cochabamba to demand he return to finish his term, which had been due to end in January.
Some farmers threw rocks at security forces and at least ten protesters were arrested, a Reuters witness said.
The region, long a bastion of Morales' support, was rocked last week by what human rights observers have described as a disproportionate use of force in the town of Sacaba after security forces shot dead up to ten anti-government protesters.