Travelling with a large entourage that included six medical people, Mugabe had difficulties disembarking from the Air Zimbabwe chartered flight at Livingstone International Airport.
During the summit at Zambezi Sun Hotel in the resort town in southern Zambia, Mugabe moved around in a golf cart.
Even disembarking from the golf cart required his optimum concentration and holding of supporting metal bars while his counterparts walked freely.
The announcement followed intense speculation during Mugabe’s annual leave that he was suffering from prostate cancer and had visited a hospital in the Far East.
Zanu PF has chosen Zimbabwe’s only ruler since independence to represent it in presidential elections expected later this year.
But analysts’ doubt that he would be fit enough to see through the usually vigorous election campaign.
His major rival would be the 59-year-old Prime Minister Morgan Tsvangirai who beat Mugabe in the first round of the 2008 presidential elections but failed to garner the majority required to claim the presidency.