Army chief General Constantino Chiwenga gave an unprecedented press conference on Monday, flanked by dozens of officers, and warned Mugabe that he would intervene if the president continued to purge the ruling Zanu-PF party.

Mnangagwa has been embroiled in a long-running feud with Mugabe’s wife Grace, 52. Both were seen as leading contenders to replace Mugabe but Mnangagwa had the tacit support of the armed forces, which viewed Grace – a political novice – with derision.

In a sign that the military was purging the first lady’s backers, a Grace loyalist widely reported to have been detained by the army appeared on state TV late on Wednesday.

Kudzai Chipanga, leader of the Zanu-PF’s youth league, apologised for criticising Chiwenga following the general’s threat to intervene against Mugabe.

“I kindly request General Chiwenga to please accept my apologies on behalf of the youth league and myself. We are still young people, we are still growing up. We learn from our mistakes,” said Chipanga, who shifted uneasily as he read the statement. – AFP

On Wednesday the African Union issued an unusually terse statement that said the situation on the ground “seems like a coup” and called on the military to pull back and respect the constitution.

Britain, Zimbabwe’s colonial ruler until independence, called for calm and warned against handing power to an unelected leader.

“Nobody wants simply to see the transition from one unelected tyrant to the next,” said British foreign minister Boris Johnson.

Zimbabwe’s army was set on a collision course with Mugabe last week when he abruptly fired his vice president Emmerson Mnangagwa – a lynchpin of the defence and security establishment. Mnangagwa, 75, was previously one of Mugabe’s most loyal lieutenants, having worked alongside him for decades.

But he fled to South Africa following his dismissal and published a scathing five-page rebuke of Mugabe’s leadership and Grace’s political ambition.