According to South African President Jacob Zuma, Mugabe is being detained at his home and unable to leave. Members of the country's military remain deployed outside the presidential palace, Zimbabwe's parliament, the airport and the state broadcaster building.
In a dramatic televised statement early Wednesday, army spokesman Maj. Gen. S.B. Moyo addressed the country, denying a military takeover, and claiming instead that the army was conducting an operation to target "criminals" close to Mugabe who were causing "social and economic suffering." Mugabe and his family, the commander said, were safe.
South African envoys: Two envoys dispatched by South African President Zuma arrived in Harare for talks Thursday.
Key ally apologizes: Kudzanai Chipan, head of the Zanu-PF Youth League, appeared on state television to issue an apology for criticizing the head of the armed forces earlier this week.
Streets 'quiet': Tanks were seen at key intersections in the city Wednesday though there were few other signs of a change in leadership.
Botswana meeting: Zuma, as chair of the Southern African Development Community (SADC), has called for a meeting in Botswana Thursday.
Zuma did not denounce the military's move, instead calling on Zimbabwe's Defense Forces to show restraint, adding that he hoped they "will not move and do more damage."
"I am hoping that the situation is going to be controlled so peace and stability comes back to Zimbabwe," he said.
Two South African ministers arrived in Zimbabwe on Wednesday to meet with authorities, according to the South African Department of International Relations and Cooperation.
A spokesperson for Zimbabwe's opposition party, the Movement for Democratic Change (MDC), called for all parties to "respect human life," saying the apparent coup was an "accident waiting to happen."
The MDC had been telling the world for years that "this is an unsustainable system," said Obert Gutu. "We haven't heard of any looting. We haven't heard of any bloodshed ... or anybody being killed."
A separate meeting of the Southern African Development Community (SADC) was called by Zuma, Thursday. The meeting, to be held in Botswana, will include foreign ministers and delegates from neighboring Angola, Tanzania and Zambia.
Calm in the streets
Even as the military positioned armored vehicles throughout downtown in the capital, residents described the environment as "quite calm."
"There are military tanks on the streets, which has never happened before," said one Harare resident. "The military is obviously now in charge despite their insistence that it's not a coup. It is."
"Activities are normal elsewhere," said another university student who was able to pass by the tanks outside of government buildings in central Harare repeatedly on Wednesday. "The soldiers outside the president's office are actually talking to folks passing by," he said.
The US embassy in Harare on Thursday urged American citizens to remain calm and safe and "limit unnecessary movements." It said that while the US government "does not take sides in matters of internal Zimbabwean politics," it said it was deeply concerned by the military's actions.
"We call on Zimbabwean military leaders to exercise restraint, respect the rule of law, uphold the constitutionally-protected rights of all citizens, and to quickly return the country to normalcy," the embassy said.
UN Secretary-General Antonio Guterres has appealed for "calm, nonviolence and restraint," deputy spokesman Farhan Haq said in a statement to CNN.
Mugabe's shock decision to dismiss his powerful deputy last week is seen as the apparent trigger for Wednesday's military intervention. A simmering succession battle in his ruling Zanu-PF party came to a head after Vice-President Emmerson Mnangagwa was fired, fueling speculation that Mugabe was preparing to hand over the reins of government to his wife Grace Mugabe, 52.
There are reports that along with the detention of Mugabe and his family, other government officials have also been arrested.
Mnangagwa remains one of the most powerful figures in the country and derives much of his support from the military.
The head of the influential Zimbabwe War Veterans Association, Chris Mutsvangwa, is an ally of Mnangagwa. In a statement released Wednesday Mutsvangwa praised the military for its actions, calling the move a "bloodless coup."
"We salute the patriotic and gallant forces of Zimbabwe for once again coming to the decisive rescue of the nation," the statement said. "The populace has long suffered under a self-saving dictatorship that had become an oligarch with dynastic delusion."
Who's in charge?
It remains uncertain, however, as to who precisely is calling the shots. In his Wednesday broadcast, Maj. Gen. S.B. Moyo insisted that people weren't witnessing a military takeover.
Redi Tlhabi, journalist and talk show host, told CNN there was a reluctance in Zimbabwe to call it a coup, for fear of intervention by the African Union and other regional bodies.
"If they say that they have staged a coup, it compels the neighboring, regional countries to intervene, Tihabi said. "Remember, all of them embraced constitutional democracy and the coup actually belongs to a bygone era. So they're reticent because they're trying to avoid that kind of intervention," added Tihabi.
Signs of shifting alliances emerged later Wednesday when the head of the Zanu-PF Youth League, a group that is a key ally of Grace Mugabe, apologized to the armed forces in a video broadcast on national broadcaster ZBC.
Earlier this week, Kudzanai Chipanga criticized the head of the armed forces in a public statement, vowing to fight and die for Mugabe.
"I have since reflected and I personally admitted that I erred together with my entire executive to denigrate your highest office," Kudzanai Chipanga said Thursday. "I have not been persuaded to offer myself to the state media but I have personally reflected and realized my mistake."
CNN's David McKenzie and Brent Swails reported from Harare, and Angela Dewan wrote from London. CNN's Joshua Berlinger, Emily Smith, Robyn Curnow,