Bolivia's interim president Jeanine Anez was forced to suspend a trip out of the capital La Paz planned for Monday, a government spokesman said, after a threat on her life by a "criminal group."
Anez, 52, had been due to travel to her native Beni province in northeastern Bolivia but the trip was canceled because of a credible threat, Interior Minister Arturo Murillo said at a news conference in La Paz.
Murillo said Venezuelans, Cubans, and Colombians were "involved," without giving further details. Anez's government on Friday asked Venezuelan officials to leave the country and accused Cuba of stoking unrest.
Both Cuba and Venezuela were close allies of socialist former president Evo Morales, who stepped down last week amid violent protests and accusations of vote-rigging in an Oct. 20 presidential election. An Organization of American States audit found irregularities in the vote.
Morales fled to Mexico but his supporters have since taken to the streets, sometimes armed with homemade weapons, barricading roads and skirmishing with security forces.
A total of 23 people have died in the unrest so far, according to a government human rights institution.
The roadblocks have caused a food and fuel crisis, resulting in long lines outside grocery stores in La Paz. A general strike called for Monday appeared by midday to have fallen flat.
Anez, a conservative former senator, took over last Tuesday.
She has promised to build bridges with Morales' Movement for Socialism (MAS) party and hold fresh elections, albeit without the participation of Morales, who ran the country since 2006.
But attempts at dialogue with Morales' supporters have faltered, with both sides trading accusations of fomenting violence.
Jerjes Justiniano, the newly-appointed presidency minister, said he would be advising Anez to "immediately" call an election by presidential decree, in the absence of an agreement.
Murillo said the government would ensure an election was held within the mandated 90-day limit.
"We are leaving in days," he said. "We will have an election. The greatest honor for a Bolivian is to become president of the country but that person must win with votes, not with bullets or boots."
Bolivia's Roman Catholic Episcopal Conference said that, together with European Union and United Nations representatives, it would seek to bring the national government and opposition parties together for fresh talks on a roadmap for elections on Monday afternoon.
"Holding new, transparent and credible elections, is the best way to overcome differences in a democratic and peaceful way," the Church said.