Harare: Zimbabwe was on a knife’s edge on Thursday after the military seized power in what it dubbed a targeted operation against ‘criminals’ in the entourage of President Robert Mugabe, who has ruled the southern African nation for almost four decades.

It was not clear whether the apparent military coup would bring a formal end to the 93-year-old Mugabe’s rule. The main goal of the generals appeared to be preventing Mugabe’s wife Grace, 41 years his junior, from succeeding him.

Local media reported South Africa’s defence and state security ministers, dispatched by President Jacob Zuma as regional envoys, arrived in Zimbabwe’s capital, Harare, on Wednesday night and were expected to meet both Mugabe and the military. Their ultimate goal was not clear.

Zuma earlier called for ‘calm and restraint’ and asked the defence forces ‘to ensure that peace and stability are not undermined in Zimbabwe,’ South Africa’s neighbour, which has lurched from crisis to crisis over the past two decades.

The South African presidency said Mugabe had told Zuma over the phone that he was confined to his home but was otherwise fine and the military said it was keeping him and his family safe.

Mugabe, still seen by many Africans as a liberation hero, is reviled in the West as a despot whose disastrous handling of the economy and willingness to resort to violence to maintain power destroyed one of Africa’s most promising states.

He plunged Zimbabwe into a fresh political crisis last week by firing his vice president and presumed successor, Emmerson Mnangagwa, 75 - known as the ‘crocodile’ - for showing ‘traits of disloyalty’.

The generals believed that move was aimed at clearing a path for Grace Mugabe to take over and said on Monday they were prepared to ‘step in’ if purges of their allies did not end.

Tanks blocked roads after dark and soldiers with automatic weapons kept up their patrols, but the situation appeared calm.

Whatever the final outcome, the events could signal a once-in-a-generation change for the former British colony, a regional breadbasket reduced to destitution by economic policies Mugabe’s critics have long blamed on him.