This article is more than 1 year old

This article is more than 1 year old

Opposition leaders in Zimbabwe say they will launch a new attempt this week to put pressure on the president, Emmerson Mnangagwa, and his ruling Zanu-PF party to share power.

Nelson Chamisa, the leader of the Movement for Democratic Change, the main opposition party in the former British colony, said a rally on Thursday in Harare would call for a “transitional authority” to “move the country forward”.

Chamisa reiterated his rejection of the results in presidential polls held four months ago. Mnangagwa was declared winner of the vote, the first after the ousting of Robert Mugabe in a military takeover last year.

“We need a collective approach ... the people voted and that has to be respected,” Chamisa told the Guardian.

Mugabe, 94, has been receiving medical treatment in Singapore for the last two months. He is unable to walk because of ill health and old age, Mnangagwa said on Saturday.

“He is now old. Of course, he now is unable to walk but whatever he asks for we will provide,” Mnangagwa told hundreds of supporters in Mugabe’s home area of Zvimba, about 60 miles (100km) west of the capital, Harare.

“We are looking after him. He is the founding father of the nation of Zimbabwe. He is our founding father of free Zimbabwe.”

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Mugabe, who took power in 1980, is expected to return to the country this week.

Mnangagwa has made strenuous attempts to convince the international community that Zanu-PF has forgone the repression and brutality that characterised its 38 years in power. He has vowed to revive Zimbabwe’s ailing economy by attracting much needed foreign direct investment.

Although the elections in July were not marred by the type of systematic violence experienced under Mugabe, alleged irregularities during the count and violent repression following the vote have resulted in lukewarm support for Mnangagwa and the ruling Zanu-PF party from major international powers.

The shooting by soldiers of six unarmed civilians in Harare during opposition protests also made endorsement of the new government difficult, officials privately admit.

To deflect some of the criticism, Mnangagwa set up an inquiry commission into the killings headed by the former South African president Kgalema Motlanthe.

Senior military commanders have told the inquiry their men were not responsible for the killings, despite widely published photographs and video footage showing Zimbabwean army soldiers firing on people in Harare’s streets.

Brig Gen Anselem Sanyatwe, the commander of the elite presidential guard, told a hearing in Harare of the special inquiry investigating the killings that “if any gunshot wounds were sustained by the victims, it was not from my men”.

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Officials have suggested that unidentified opposition activists were responsible for the deaths and have alleged that Chamisa incited violence. The MDC leader, 40, dismissed the accusation as “bizarre”.

Chamisa has been invited to appear before the inquiry but said he was concerned about its impartiality and was still to take a decision.

“It would frankly be embarrassing for me to come to answer wild assertions made by a member of the state, not a court of law, not an ordinary person … How do you appear before a panel appointed by a political competitor?” Chamisa said. A response from the inquiry to a letter Chamisa sent outlining his principal concerns had been unsatisfactory, he said.

Zimbabwe faces a deepening economic crisis as hopes fade of a new wave of international investment and aid. Fuel has run short and prices are soaring. Despite the hardship, mobilisation for opposition protests has remained at relatively low levels.