In what appears to be the first punitive measure by an African country to enforce a power-sharing agreement, the South African government said it was "extremely concerned" about Zimbabwe's political impasse, which has deepened a humanitarian crisis, and called for "mature leadership" to resolve outstanding issues, Reuters reported.
Last month, South Africa approved $28.3 million in agricultural aid to Zimbabwe, subject to conditions, to help short-term food needs.
The U.S. ambassador to Harare also said Thursday that a total of 294 people have been confirmed dead from water-borne cholera in Zimbabwe.
"There are over 1,200 confirmed cases of cholera and another 2,500 unconfirmed cases of cholera," James McGee told reporters, adding that the death toll had risen higher than the official toll.
Humanitarian organization Doctors Without Borders said Tuesday that 1.4 million people are at risk of the disease in Harare alone, and cases of cholera have been detected as far away as South Africa's southern coast.
"No amount of political disagreement can ever justify the suffering that ordinary Zimbabweans are being subjected to at the moment," the South African cabinet's statement said.
The statements from South Africa came as President Mugabe's ruling ZANU-PF and the opposition Movement for Democratic Change prepared to hold another round of talks in South Africa next week to seek a breakthrough while political tensions are rising.
"We're going to make sure that everything is done to force the parties to go back to the negotiating table," said South African cabinet spokesman Themba Maseko, according to Reuters.
McGee also told reporters Thursday that international pressure has failed to weaken President Mugabe's power.
Western and African countries have been trying to persuade Mugabe with sanctions and threats of isolation to follow through on a Sept. 15 power-sharing agreement with opposition leader Morgan Tsvangirai, who won presidential elections in March but withdrew from a run-off election after violence against his supporters.
Tsvangirai insisted that under the power-sharing deal, his party should be given ministries related to security, such as police, in any unity government. Only the finance ministry has been offered to the opposition.
Mugabe, in power since independence from Britain in 1980, is trying to push through a constitutional amendment allowing him to name a cabinet.
"He does have the absolute authority of the heads of the security forces," McGee said. Change will have to come from political pressure within Zimbabwe, he said.
Meantime, Zimbabwe's government has denied a report that it was blocking a visit from former U.N. Secretary-General Kofi Annan, former U.S. President Jimmy Carter, and human rights activist and Nelson Mandela's wife Graca Machel. They will visit the country Friday.
"The purpose of our visit is to meet those working on the ground to better assess the extent of the crisis and how assistance can be improved," Annan said.