Morales said it had been a "colossal mistake" for his government not to have a "plan B" that would have allowed his Movement for Socialism party to hold onto power in the face of mounting pressure from opposition demonstrators.
He said he intends to return to Bolivia when campaigning for the elections starts, despite the risk of arrest. "Before long, if I return to Bolivia, we will have to organise popular armed militias, as Venezuela has done," Morales told RKC.
He confirmed to the Reuters nes agency that the recording was genuine, but added that he did not want people to arm themselves with guns.
Lopez, who was previously in the military, insisted: "We're not going to allow anything."
Añez said on Twitter that Morales's statements showed that "peace, reconciliation and democracy were never options for him."
Morales tweeted that indigenous peasant movements had defended themselves in the past.
"In some regions it was called a communal guard; In other times: militias. Now, union police or union security. All within the framework of our uses and customs, and respecting the Constitution," he tweeted.
In Venezuela, about 3.2 million civilians belong to a militia created by former president Hugo Chávez, an ally of Morales and mentor of the country's current socialist President Nicolás Maduro.
Those militias — known as colectivos in Venezuela — have been accused by NGOs of carrying out violent oppression against opposition protesters.