Mr. Bush joined several other Western leaders calling for Mugabe to resign as a cholera outbreak rages across Zimbabwe. Death figures rose to around 600 Tuesday, and reports from the World Health Organization feared the disease could infect as many 60,000 if not handled properly.
Amid the increased pressure from Western powers, the African Union rejected plans Tuesday to use force against Mugabe, who reached the early stages of a power-sharing agreement with opposition leader Morgan Tsvangirai in September.
Negotiations between Mugabe's ruling party and Tsvangirai's opposition party to form a unity government remain stalled after widely disputed presidential elections earlier in the year.
"We have a serious humanitarian crisis in Zimbabwe. We have cholera. Do they think that we can eradicate cholera with guns?" A.U. spokesman Salva Rweyemamu asked, according to Reuters.
Rweyemamu said proposals to intervene with peacekeeping troops or oust Mugabe by force, which were among the options suggested by Kenyan Prime Minister Raila Odinga and Nobel peace laureate and South African Archbishop Desmond Tutu, were not being considered.
Tutu told a Dutch TV station last week hat African leaders cannot stand by any longer. "If they say to [Mugabe], step down, and he refuses, they must go in . . . militarily," Tutu said, according to the Wall Street Journal
"Only dialogue between the Zimbabwean parties, supported by the African Union and other regional actors, can restore peace and stability to that country," he said.
South Africa is also poised to oppose any move to send troops to Zimbabwe, a senior government official there told news agencies.
In his statement, President Bush praised African leaders who are speaking out against Mugabe.
"Across the continent, African voices are bravely speaking out to say now is the time for him to step down," Mr. Bush said.
President Bush said the U.S. will continue to work with other countries "to halt the violence and stem the humanitarian disaster that the Mugabe regime is inflicting on its people. We stand ready to help rebuild Zimbabwe once a legitimate government has been formed that reflects the results of the March elections. "
Last week, U.S. Secretary of State Condoleezza Rice called for Mugabe to leave office. "It's well past time for Robert Mugabe to leave," Rice said in Copenhagen.
A spokesman for Mugabe accused the West of using the cholera epidemic, for which Zimbabwe has declared a state of emergency, as a political excuse for bringing down the 84-year-old 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 spokesman George Charamba as saying.
While the African Union and Zimbabwean government are resisting Western demands, they have also called for international and regional aid to help fight the spread of cholera across the country. Zimbabwe's Director General of the Department of Foreign Affairs asked that South Africa increase its humanitarian aid to its neighbor, according to Reuters.
With nearly 14,000 afflicted with the disease, according to the United Nations, the International Red Cross is desperately seeking increased assistance to deal with the cholera crisis.
IRC representative for Zimbabwe, Peter Lundberg, told the Associated Press Tuesday the Red Cross had "exhausted initial cholera treatment and water purification supplies, and was preparing an appeal for more donations and cash."
"Zimbabwe is grappling with a cholera crisis of unprecedented levels," a report from the United Nation's children's organization, UNICEF, said. "Schools and hospitals are closing, patients cannot access health care, teachers, nurses and doctors are not able to come to work."
In an address at The Hague, former U.N. Secretary-General Kofi Annan said Tuesday "the abject failure of" Zimbabwe's leadership has the country "now moving rapidly to becoming a full-blown failed state," Reuters reported.
Even traditional allies of Zimbabwe's leadership are calling for government compromise in order to receive more help, with China pushing for Mugabe and Tvangirai to form a functional coalition government.
"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, according to Reuters.