Questions remain over the future of Robert Mugabe, who ruled Zimbabwe for 37 years, and his wife who just days ago was poised to succeed him.

The 93-year-old, who resigned on Tuesday as MPs began impeaching him, has not spoken publicly since his stunning speech on Sunday night defying calls from the military, ruling party and the people to step down.

Mr Mugabe appeared to remain in the capital, Harare, with former first lady Grace, but it was not clear under what terms.

A new photo circulating on social media, said to be taken this week, showed Mr Mugabe and his wife sitting on a sofa with advisers standing behind them. A dejected-looking Grace Mugabe, who had been likely to replace Emmerson Mnangagwa after his firing as vice president earlier this month, looks off camera while Robert Mugabe’s eyes are closed. The photo could not immediately be verified.

Mr Mnangagwa is set to be sworn in on Friday morning at a 60,000-seat stadium after making a triumphant return to the country. He fled shortly after his firing, claiming threats to his life.

His speech upon his return on Wednesday night outside ruling party headquarters promised “a new, unfolding democracy” and efforts to rebuild a shattered economy. But he also recited slogans from the ruling ZANU-PF party, declaring death to “enemies”, that are unlikely to reassure the opposition.

Supporters hail president-in-waiting Emmerson Mnangagwa - known as the 'Crocodile'Supporters hail president-in-waiting Emmerson Mnangagwa – known as the ‘Crocodile’ (Ben Curtis/AP)

The opposition party MDC-T, which supported Mr Mugabe’s removal, said it had not been invited to the inauguration. Spokesman Obert Guru said the party was closely watching Mr Mnangagwa’s next moves, “particularly regarding the dismantling of all the oppressive pillars of repression”.

In a new statement on Thursday, Mr Mnangagwa urged Zimbabweans against “vengeful retribution”.

The pastor who led large anti-government protests last year, Evan Mawarire, said Zimbabweans should let Mr Mnangagwa know that the country should be for everyone and not just the ruling party.

Mr Mnangagwa is a former justice and defence minister with close ties to the military who served for decades as Mr Mugabe’s enforcer, a role that earned him the nickname “Crocodile”.

Zimbabwean military personnel take part in rehearsals for the presidential inauguration of Emmerson Mnangagwa Zimbabwean military personnel take part in rehearsals for the presidential inauguration of Emmerson Mnangagwa ( Ben Curtis/AP)

Many opposition supporters believe he was instrumental in the army killings of thousands of people when Mr Mugabe moved against a political rival in the 1980s, and he remains on a US sanctions list over allegations of violently cracking down on opponents.

Mr Mnangagwa, who fled Zimbabwe after being fired on November 6, was in hiding during the week-long political drama that led to Mr Mugabe’s resignation. His appearance on Wednesday, flanked by heavy security, delighted supporters who hope he can guide Zimbabwe out of political and economic turmoil that has exacted a heavy toll on the southern African nation of 16 million.

The 75-year-old said he had received messages of support from other countries. “We need the cooperation of the continent of Africa,” he said. “We need the cooperation of our friends outside the continent.”