"It is time for Robert Mugabe to go," Bush said in a statement. "Across the continent, African voices are bravely speaking out to say now is the time for him to step down."
Earlier of the African Union rejected tougher action against Zimbabwe’s President Robert Mugabe on Tuesday after demands from Western leaders and some African statesmen that he quit over a growing humanitarian crisis.
The death toll neared 600 from a cholera epidemic which Mugabe’s government accuses Western powers of exploiting to try to force his departure. The World Health Organisation said cholera could affect as many as 60,000 in a worst-case scenario.
"Only dialogue between the Zimbabwean parties, supported by the AU and other regional actors, can restore peace and stability to that country," said Salva Rweyemamu, spokesman for AU chairman and Tanzanian President Jakaya Kikwete.
Rweyemamu said sending peacekeeping troops or removing Mugabe by force, as proposed by prominent figures including Kenyan Prime Minister Raila Odinga and Nobel peace laureate and South African Archbishop Desmond Tutu, were not options.
"We have a serious humanitarian crisis in Zimbabwe. We have cholera. Do they think that we can eradicate cholera with guns?"
South Africa will oppose any move to send troops to Zimbabwe, a senior government official there said. Ayanda Ntsaluba, Director General of the Department of Foreign Affairs, told reporters that South Africa needed to increase humanitarian aid to its neighbour.
Mugabe and opposition leader Morgan Tsvangirai reached a power-sharing deal brokered by regional mediator Thabo Mbeki, South Africa’s former president, in September. But they are deadlocked over how to implement it.
The spreading cholera, coupled with chronic food shortages, has highlighted the economic collapse of the southern African country, once relatively prosperous. Basic foodstuffs are running out and prices of goods have been doubling every 24 hours.
Zimbabwe on Tuesday ordered prices of goods and services to be cut to December 3 levels after prices surged tenfold when the central bank increased bank withdrawal limits.
A loaf of bread cost 30 million Zimbabwe dollars — worth $1 on the black market — on Tuesday, compared to 2.5 million Zimbabwe dollars last Wednesday. The 100 million Zimbabwe dollars people are allowed to withdraw from banks each week can only buy three loaves of bread.
A similar price freeze in June 2007 badly affected local businesses and left Zimbabwe battling shortages of basic goods.
Mugabe’s spokesman George Charamba said the West was using the cholera outbreak to try to bring down the veteran leader.
"The British and the Americans are dead set on bringing Zimbabwe back to the U.N. Security Council, they are also dead set on ensuring that there is an invasion of Zimbabwe but without themselves carrying it out," state-owned newspaper The Herald quoted Charamba as saying.
In a sign that Mugabe’s traditional ally China may be distancing itself, Beijing stressed the need for the formation of a unity government between Mugabe and the opposition.
"We sincerely hope that all concerned parties in Zimbabwe will truly focus on the interests of the country and its people and soon form a government of national unity," Chinese Foreign Ministry spokesman Liu Jianchao said in Beijing.
China offered aid, saying it was concerned about the deteriorating political and economic situation. Liu said China supported African mediation efforts in Zimbabwe.
Former U.N. Secretary-General Kofi Annan said on Tuesday Zimbabwe had failed as a state. "Due to the abject failure of its leadership, it is now moving rapidly to becoming a full-blown failed state," Annan said in an address in The Hague.
The U.N. Office for the Coordination of Humanitarian Affairs said the number of cholera cases stood at 13,960, with 589 deaths. "It is total chaos, three hospitals in Harare are closed due to a lack of personnel," spokeswoman Elisabeth Byrs said.
The World Health Organisation (WHO) said up to 60,000 could catch cholera if the epidemic gets out of control. The disease is preventable and treatable under normal circumstances, but Zimbabwe’s health sector is near collapse.
The WHO said it was considering financial incentives for unpaid health workers in Zimbabwe to return to their jobs.
Mugabe blames Western sanctions for Zimbabwe’s hardship, while his critics accuse him of increasingly authoritarian rule.
South Africa, receiving hundreds of desperate Zimbabweans seeking treatment for cholera, is due to give details of an aid package to Zimbabwe later this week. At least eight people have died from cholera in the Limpopo province bordering Zimbabwe.