Zimbabwe's President Robert Mugabe has made his first public appearance since the country's army took over on Wednesday.

He attended a graduation ceremony in the capital, Harare.

In an apparent display of defiance, the 93-year-old arrived at the ceremony on Friday morning dressed in a blue academic gown and tasselled hat.

Mr Mugabe had been under house arrest for days. The army made its move after a power struggle over his successor.

The military said on Friday it was "engaging" with Mr Mugabe and would advise the public on the outcome of talks "as soon as possible".

A witness quoted by Reuters news agency says Mr Mugabe was cheered by the crowd at the graduation ceremony after he spoke.

The army took control after Mr Mugabe last week sacked Vice-President Emmerson Mnangagwa, signalling that he favoured his wife Grace Mugabe to take over his Zanu-PF party and the presidency.

A senior source in Zanu-PF told Reuters news agency the party was due to meet on Friday to draft a motion to fire Mr Mugabe on Sunday. If Mr Mugabe still refuses to stand down, the party plans to impeach him on Tuesday, according to the source.

Talks with Mr Mugabe continued, the military said in a statement reported by the state-run Herald newspaper and Zimbabwe Broadcasting Corporation.

Zimbabwe's military is "currently engaging with the Commander-in-Chief President Robert Mugabe on the way forward and will advise the nation of the outcome as soon as possible," the statement said.