Update 11.20am: Robert Mugabe is "fine" but is confined to his home after a night of unrest in Zimbabwe that included a military takeover of the state broadcaster, South African president Jacob Zuma has said.
Mr Zuma said he had spoken with 93-year-old Mr Mugabe, who he continues to refer to as president of Zimbabwe.
South Africa's ministers of defence and state security are being sent to Zimbabwe to meet with Mr Mugabe and the military, Mr Zuma said.
Zimbabwe's army said it had Mr Mugabe and his wife in custody and is securing government offices following a night of unrest.
Reports are now emerging that his wife, Grace Mugabe, is believed to have left for Nambia.
The night's action triggered speculation of a coup but the military's supporters praised it as a "bloodless correction".
For the first time, the southern African nation is seeing the military oppose Mr Mugabe, the world's oldest head of state and one of the longest-serving authoritarian rulers.
Mr Mugabe has been in power since Zimbabwe's independence from white minority rule in 1980.
The move comes after Mr Mugabe last week fired vice president Emmerson Mnangagwa.
Mr Mnangagwa - who enjoyed the military's backing - fled Zimbabwe last week but said he would return to lead the country.
More than 100 senior officials allegedly supporting him have been listed for disciplinary measures by a faction associated with Mr Mugabe's wife Grace.
The first lady appeared positioned to replace Mr Mnangagwa as one of the country's two vice presidents at a special conference of the ruling party in December, leading many in Zimbabwe to suspect she could succeed her husband.
Grace Mugabe is unpopular with some Zimbabweans because of lavish spending as many struggle and four people accused of booing her at a recent rally were arrested.
Armed soldiers in armoured personnel carriers stationed themselves at key points in capital Harare while Zimbabweans formed long lines at banks in order to draw the limited cash available, a routine chore in the country's ongoing financial crisis.
Update 7.14am: Zimbabwe’s army has said it has President Robert Mugabe and his wife in custody and is securing government offices and patrolling the capital’s streets following a night of unrest that included a military takeover of the state broadcaster.
The night’s action triggered speculation of a coup, but the military’s supporters praised it as a "bloodless correction".
Armed soldiers in armoured personnel carriers stationed themselves at key points in Harare, while Zimbabweans formed long lines at banks in order to withdraw the limited cash available, a routine chore in the country’s ongoing financial crisis.
People looked at their phones to read about the army takeover and others went to work or to shops.
In an address to the nation after taking control of the Zimbabwe Broadcasting Corporation, an army spokesman said early this morning that the military was targeting "criminals" around Mugabe, and sought to reassure the country that order would be restored.
It was not clear where Mugabe, 93, and his wife were today, but it seems they are in the custody of the military. "Their security is guaranteed," the army spokesman said.
"We wish to make it abundantly clear that this is not a military takeover," the army statement said. "We are only targeting criminals around (Mugabe) who are committing crimes that are causing social and economic suffering in the country in order to bring them to justice."
The spokesman added that "as soon as we have accomplished our mission, we expect that the situation will return to normalcy".
The army spokesman called on churches to pray for the nation. He urged other security forces to "cooperate for the good of our country," warning that "any provocation will be met with an appropriate response".
The statement called on troops to return to barracks immediately, with all leave cancelled.
Overnight, at least three explosions were heard in the capital, Harare, and military vehicles were seen in the streets.
The military actions appear to put the army in control of the country.
Army commander Constantino Chiwenga had threatened on Monday to "step in" to calm political tensions.
Mugabe’s ruling ZANU-PF party responded by accusing the general of "treasonable conduct". But now Chiwenga appears to be in control.
Zimbabwe has not had a coup. There has been a decision to intervene because our constitution had been undermined, in the interim Comrade E Mnagngawa will be president of ZANU PF as per the constitution of our revolutionary organisation.— ZANU PF (@zanu_pf) November 15, 2017
Last night the first family was detained and are safe, both for the constitution and the sanity of the nation this was necessary. Neither Zimbabwe nor ZANU are owned by Mugabe and his wife. Today begins a fresh new era and comrade Mnangagwa will help us achieve a better Zimbabwe.— ZANU PF (@zanu_pf) November 15, 2017
ZANU PF has a way of solving our own problems, the situation is stable and Zimbabwe is open for business. There was no coup, but a bloodless peaceful transition- the centre is strong and there is peace with honest leadership.— ZANU PF (@zanu_pf) November 15, 2017
The army has been praised by the nation’s war veterans for carrying out "a bloodless correction of gross abuse of power".
Chris Mutsvangwa, chairman of the war veterans’ association, said in Johannesburg that the military will return Zimbabwe to "genuine democracy" and make the country a "modern model nation".
Mutsvangwa and the war veterans are staunch allies of Emmerson Mnangagwa, who was fired from his post of vice president by Mugabe last week. Mnangagwa fled Zimbabwe last week but said he would return to lead the country.
The US Embassy closed to the public today and encouraged citizens to shelter in place, citing "the ongoing political uncertainty through the night".
For the first time, this southern African nation is seeing an open rift between the military and Mugabe, the world’s oldest head of state who has ruled since independence from white minority rule in 1980. The military has been a key pillar of his power.
Robert Mugabe's legacy as one of the most ruthless tyrants of modern times will remain long after his days as notorious statesman of Zimbabwe are over.
Mugabe's savage rule over Zimbabwe was dominated by murder, bloodshed, torture, persecution of political opponents, intimidation and vote-rigging on a grand scale.
He was the man who, in 1980, became the head of government of Zimbabwe, chosen to guide the country towards "democracy" after 14 years of rebellion against the Crown headed by white Southern Rhodesian leader Ian Smith.
Much of Mugabe's dirty work was carried out by his bullying henchmen, "veterans" of the guerrilla war against the Smith regime.
As Mugabe grew into his 70s he became paranoid. He believed his opponents were trying to kill him.
Any voice of dissidence was met with violence and, in the case of an independent newspaper, shut down.
In 2008 and 2009, the state's central bank printed so much of its currency - theZimbabwe dollar - that the country experienced mind-boggling hyperinflation that reached 500 billion per cent, according to the International Monetary Fund.
The result was that items such as a loaf of bread would often cost millions ofZimbabwean dollars.
Inflation was only brought under control when the government abandoned theZimbabwe currency and used the US dollar as its main medium of trade. Last year this was replaced with a new currency called bond notes.
In late 2015 he was awarded China's alternative to the Nobel Peace Prize, the Confucius Peace Prize, for what its committee called his inspired national leadership and service to pan-Africanism.