Three explosions were heard in Zimbabwe's capital Harare on Wednesday as military vehicles were seen in streets. Mnangagwa fled to South Africa but is rumoured to have returned to Zimbabwe on Wednesday to take control of government.
Two hours later, soldiers overran the headquarters of the ZBC, and ordered staff to leave. "We wish to assure the nation that his excellency the president. and his family are safe and sound and their security is guaranteed".
"As soon as we accomplish our mission we expect situation to return to normalcy", Moyo said.
In the statement, the ruling party said it stood by the "primacy of politics over the gun" and accused General Chiwenga of "treasonable conduct ... meant to incite insurrection".
Tensions were raised further on Tuesday when armoured vehicles were seen taking up positions on roads outside Harare, although their objective was unclear.
Both the United States and British embassies in Zimbabwe have advised their nationals to stay indoors because of what they call the 'uncertain situation'. But a military spokesman has denied this is a coup despite rumours that Mugabe and his family are under house arrest.
Mugabe and his wife grace, who is 41 years his junior.
Mnangagwa's dismissal left Mugabe's wife Grace, 52, in prime position to succeed her husband as the next president - a succession strongly opposed by senior ranks in the military.
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Robert Mugabe has accumulated a net worth of $10 million (£7.5 million) thanks largely to the fortunes reaped from Zimbabwe's diamond deposits.
The US embassy in the capital said it would be closed on Wednesday due to the "uncertainty", while advising US citizens to "shelter in place".
In a statement attributed to Mnangagwa at the time he reportedly left for self-imposed exile, he promised to return to Zimbabwe to "lead" the country, warning Mugabe that the ZANU PF party was not his personal property.
Tensions between the veteran leader and the military, which has long helped prop up his authoritarian rule, have erupted in public in recent days.
However, just a week after Mugabe, 93, fired longtime vice president and liberation war veteran Emmerson Mnangagwa, accusing him of disloyalty and disrespect, an account purporting to belong to the ruling ZANU PF party tweeted that Mnangagwa had been installed as the party's interim president.
Despite an often abrasive manner, Grace Mugabe's commanding presence and charity work have won support from some Zimbabweans.
Target: The military say they are going after "criminals".
Mugabe's firing of Vice President Emmerson Mnangagwa, his right-hand man for almost four decades, stunned the nation.More news: 'Justice League's Ray Fisher Reveals Cyborg Easter Egg In Batman V Superman
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