Zimbabwean President Robert Mugabe has blocked a fact-finding mission to his country by three senior international figures, including former United Nations Secretary-General Kofi Annan and former American President Jimmy Carter.

At a press conference in Johannesburg last week, Annan said the delegation – also including Nelson Mandela’s wife, Graca Machel – had been informed that they would not be granted visas on arrival in the capital city, Harare.

“We need no red carpet treatment from the government of Zimbabwe,” said Annan. “We seek no permission other than to help the desperate. We had to cancel our visit, which was humanitarian in nature, because the government made it very clear that they will not co-operate.”

The Zimbabwean government denied it had refused entry to the three delegates, rather advised them to reschedule their visit to a ‘mutually agreed date in the future.’ In the past few weeks, Zimbabwean state media reported that the government considered the aborted mission biased, due in part to Archbishop Desmond Tutu’s links to the group. His repeated statements about the human rights violations in Zimbabwe are generally understood to have annoyed Mugabe.

“It is quite clear that no meaningful assessment of the humanitarian situation could be undertaken in the few hours the delegation intended to be in Zimbabwe,” said Foreign Affairs Minister Simbarashe Mumbengegwi. “It is on this basis that Mr. Annan was advised, in good time, to postpone the visit.”

The events unfolded before a background of cholera epidemic caused by the collapse of the water and sanitation network and worsened by the onset of the rainy season.

Six hundred have been infected, and 300 have died thus far. South Africa – where three have died and at least 100 have been infected - has called for urgent help from the World Health Organization to handle a new influx of Zimbabweans crossing the border into Limpopo province to flee the crisis.

Fears of xenophobic violence, sparked by pressure from the migrants on the nation’s weak medical infrastructure, prompted South Africa’s first-ever move to exert overt pressure on Zimbabwe’s political rivals to make a deal last week. The cabinet voted to delay a £19m package of seed and fertilizer aid, and stated the cholera outbreak was a ‘clear indication that ordinary Zimbabweans are the true victims of their leaders’ lack of political will ‘.

The South African mediator and former President Thabo Mbeki is hoping to convene further talks in Johannesburg this week, amid signals from Mugabe that he plans to forge ahead with forming a government, despite disagreements with the MDC over its composition.