Robert Mugabe has made his first public appearance since a military take over on Wednesday appeared to aim at ending his 37-year rule.

The president arrived at a university graduation ceremony on the outskirts of the capital Harare on Friday. Wearing a blue and yellow academic gown and mortar board hat, the 93-year-old was greeted by cheers from the crowd as he declared the ceremony open and sat in large wooden chair at the front the hall.

The self-styled grand old man of African politics, the only leader Zimbabwe has known since independence in 1980, insists he is still in charge after a military statement on government-controlled television aimed to quell concerns of rising chaos.

The army is under pressure to outline its plans after arresting around a dozen officials and leading members of the G40, a faction of the ruling Zanu-PF party loyal to Grace Mugabe, the president's wife.

Mugabe is refusing to negotiate with Father Fidelis Mukunori, a Catholic priest and chaplain to the president, who is leading the mediation to arrange a deal for his departure. 

But the source, a senior member of Mugabe's ZANU-PF party, made clear the party wanted him gone.

'If he becomes stubborn, we will arrange for him to be fired on Sunday,' the source said according to Reuters. 'When that is done, it's impeachment on Tuesday.'

Zimbabwe's official newspaper, the Herald, ran photographs late on Thursday that showed a grinning Mugabe shaking hands with military chief General Constantino Chiwenga, who seized power this week.

That suggested Mugabe was managing to hold out against Chiwenga's coup, with some political sources saying he was trying to delay his departure until elections scheduled for next year.

The ZANU-PF source said that was not the case. Anxious to avoid a protracted stalemate, party leaders were drawing up plans to dismiss Mugabe at the weekend if he refused to quit, the source said.

'There is no going back,' the source told Reuters. 'It's like a match delayed by heavy rain, with the home side leading 90-0 in the 89th minute.'

It comes as the Archbishops of Canterbury and York offered prayers for Zimbabwe. Justin Welby said: 'I am praying for the whole nation of Zimbabwe – its people, its military, its political leaders – that they may find a path forward that leads to the flourishingof this nation and all its people.

He added: 'To the Church in Zimbabwe: your brothers and sisters around theAnglican Communion stand with you in prayer, solidarity and hope. Your faith, courage and persistence in the face of difficult times has long been an example to the world. May God strengthen, protect and guide you as you seek to bear witness to the love of Christ at this deeply challenging time.'

Although Mugabe is holding out it seems he has few remaining options. He has little backing in the capital, a hotbed of support for the opposition, which has tapped into the anger and frustration at his handling of the economy, which collapsed after the seizure of white-owned farms in 2000.

Unemployment is now running at nearly 90 percent. Chronic shortages of hard currency are driving up the price of imports as much as 50 percent a month. 

In a statement broadcast on national television, the military said it was 'engaging' with Mugabe and would announce an outcome as soon as possible.

The United States, a longtime Mugabe critic, is seeking 'a new era', the State Department's top official for Africa said, an implicit call for Mugabe to quit.

In an interview with Reuters, acting US Assistant Secretary of State for African Affairs Donald Yamamoto appeared to dismiss the idea of keeping Mugabe in an interim or ceremonial role.

'It's a transition to a new era for Zimbabwe, that's really what we're hoping for,' Yamamoto said.

The army appears to want Mugabe to go quietly and allow a smooth and bloodless transition to Emmerson Mnangagwa, the vice president, whose sacking last week triggered the military takeover.