Bolivian President Luis Arce denounced the "irregular mobilisation" of some army units in La Paz on Wednesday and former leader Evo Morales accused a top general of plotting a coup.
Heavily armed soldiers and armored vehicles were seen gathering in the capital's central Plaza Murillo, according to videos shared on social media.
"The three chiefs of the armed forces have come to express our dismay. There will be a new cabinet of ministers, surely things will change, but our country cannot continue like this any longer," General Juan Jose Zuniga told a local TV station.
Morales, who has publicly split with Arce although both belong to the same socialist movement, announced a national mobilisation of his supporters to back democracy.
He accused Zuniga of seeking to stage a coup and announced a general work stoppage including a call to block roadways.
Morales said: "We will not allow the armed forces to violate democracy and intimidate people."
