South African government ministers are in Harare for crisis talks with ousted President Robert Mugabe and military leaders who have seized control.
They are trying to reach a deal on the future of Zimbabwe and the man who has led the country for 37 years and is now under house arrest.
The Southern African Development Community (Sadc) regional bloc is to hold emergency talks shortly.
But sources suggest Mr Mugabe may be resisting pressure to resign.
They say Mr Mugabe is insisting he remains the legitimate president. Regional bodies such as Sadc and African Union (AU) will be keen to reach a constitutionally sound resolution to the crisis rather than to endorse a military takeover, say correspondents.
Why did the military take this action?
President Mugabe, 93, has been in control of Zimbabwe since it threw off white minority rule in 1980.
However, the power struggle over who might succeed him, between his wife Grace Mugabe and her rival former Vice-President Emmerson Mnangagwa, has split the ruling Zanu-PF party in recent months.
Last week, Mr Mugabe came down in favour of his wife, sacking Mr Mnangagwa, a veteran of Zimbabwe’s anti-colonial struggle and of Zanu-PF.
That proved too much for military leaders who seized control of the country on Wednesday.
So what’s going on in Harare now?
The capital has been on edge.
Mr Mugabe has been under house arrest. A Roman Catholic priest known to him for years, Father Fidelis Mukonori, is trying to mediate a deal on his future with the military.
South African Defence Minister Nosiviwe Maphisa-Nqakula and State Security Minister Bongani Bongo are meeting Mr Mugabe on behalf of the SADC, which South Africa currently leads.
Sticking points are said to include what role Mr Mnangagwa will play and the security of Mr Mugabe’s family.
Zanu-PF’s UK representative, Nick Mangwana, has suggested to the BBC that Mr Mugabe could remain nominally in power until the party congress in December, when Mr Mnangagwa would be formally installed as party and national leader.
Reuters news agency is quoting a source as saying Mr Mugabe’s wife Grace is in Mr Mugabe’s compound, along with senior figures from the “Generation-40” group supportive of the first lady – cabinet ministers Jonathan Moyo and Saviour Kasukuwere,
What do the South Africans want to achieve?
South Africa is hosting millions of Zimbabweans who fled after the country’s economy crashed in 2008. It has a special interest in seeing stability restored.
The Sadc mission will be pushing for a democratic solution. The body, which represents 16 countries, does not support coup-led governments as this would set a dangerous precedent in the largely peaceful region, says the BBC’s Pumza Fihlani in Johannesburg.
A Sadc emergency meeting is scheduled to take place in Botswana at 15:00 local time (13:00 GMT) to try to help find a resolution.
And Zimbabwe’s opposition?
One Zimbabwean opposition leader, Tendai Biti, told the BBC he wanted to see a transitional authority in place.
“It is urgent that we go back to democracy,” he said. “It is urgent that we go back to legitimacy but we need a transitional period and I think, I hope, that dialogue can now be opened between the army and Zimbabweans.”
He later told Reuters that he would join a national unity government if Morgan Tsvangirai, head of the Movement for Democratic Change-Tsvangirai (MDC-T) party, was also in it. Mr Tsvangirai has been abroad receiving treatment for cancer.
What’s happened to Grace Mugabe’s supporters?
Reports suggest that the military are now trying to quash the threat posed by Mrs Mugabe and her allies.
On Wednesday, one of her key allies, Zanu-PF youth wing leader Kudzai Chipanga, made a televised apology for criticising the head of the army as a war of words raged prior to the military takeover.
Mr Chipanga is thought to be in army custody but insisted his statement was voluntary.
Local media reports say a number of other senior members of the “Generation-40” group supportive of the first lady have been detained.
What are Zimbabweans being told?
Zimbabwe’s media usually toe the government line and today’s lead stories make it clear there is a new line to follow.
There is a striking absence of tough questions about what the army is doing.
The Herald, a government-owned newspaper. Yesterday it reassured readers there was “No military takeover”.
State TV and radio stations have returned to regular programming, with Thursday’s lunchtime news bulletin on state TV giving little indication of the political upheaval.
Some privately owned newspapers have dared to address the possible end of Robert Mugabe’s rule.
There have been no reports of unrest in Zimbabwe. Correspondents say many people have accepted that President Mugabe is being eased from office. Streets in Harare are said to be quieter than usual but people are going about their business.
On Wednesday, troops and armoured vehicles encircled parliament and other key buildings.
Hours earlier, soldiers took over the headquarters of national broadcaster ZBC and issued a statement saying that the military was targeting “criminals” around President Mugabe.