It was unclear n Wednesday moring who was behind the military action, RFI's correspondent Ryan Truscott said.
"The catalyst seems to have been the sacking of Vice-President Emmerson Mngangawa last week," he reported. "We've always heard that he was backed by the army but we didn't know how far down the ranks that support went."
In a statement read on the state broadcaster ZBC by Major-General Sibusiso Moyo, the Zimbabwe Defence Force said that the president and his family were safe and sound and their security was guaranteed.
Sporadic gunfire was heard last night and, as dawn broke in the capital Harare, it became apparent that the army was firmly in control.
There have been no reports of casualties.
Armoured vehicles blocked access to government buildings and parliament, while soldiers are conducting traffics and carrying out checks at road blocks.
News also emerged of several arrests of members of Mugabe’s inner circle and high-ranking members of the ruling Zanu-PF party, among them Finance Minister Ignatious Chombo and the leader of the youth wing, Kudzai Chipanga.
The US embassy in Harare has warned its citizens in the country to "shelter in place" due to "ongoing political uncertainty".
The British and Canadian Embassies remained closed on Wednesday.