President Robert Mugabe fired Mnangagwa after accusing him of not being loyal.
On Wednesday reports said soldiers deployed across the Zimbabwe capital Harare seized the state broadcaster after Mugabe's ruling Zanu-PF party accused the head of the military of treason‚ prompting frenzied speculation of a coup.
Isaac Moyo‚ Zimbabwe's ambassador to neighbouring South Africa‚ earlier dismissed talk of a coup‚ saying the government was "intact" and blaming social media for spreading false information.