NAIROBI, Kenya (CNN) -- The prime minister of Kenya Sunday called for troops to "dislodge" Zimbabwean President Robert Mugabe as the country's humanitarian crisis worsens.
A man pushes his relative in a wheelbarrow to a clinic where cholera victims are being treated in Zimbabwe.
Kenyan Prime Minister Raila Odinga said the international community must "respond to the call of the African people, and must help end the murderous reign of Robert Mugabe in Zimbabwe."
The United Nations has said more than half of Zimbabwe's population is in dire need of food and clean water.
The country is suffering from a cholera outbreak that has killed close to 600 people since August.
"The crisis in Zimbabwe has now reached a point where further lack of action by the African Union and the international community will constitute nothing less than a crime against humanity," said Odinga, a long-time critic of Mugabe.
The African Union "must formulate a resolution to send African Union troops into Zimbabwe," he said. "If no troops are available, then the AU must allow the U.N. to send its forces into Zimbabwe with immediate effect, to take over control of the country and ensure urgent humanitarian assistance to the people dying of cholera and starvation." Watch more about the cholera crisis in Zimbabwe »
If Zimbabwe's president does not cooperate, Odinga said, international troops should "dislodge Mugabe from power."
Cholera, a water-borne disease, is on the increase in nine of Zimbabwe's 10 provinces, according to the U.N. Office for the Coordination of Humanitarian Affairs (OCHA). It blamed "poor water and sanitation supply, a collapsed health system and limited government capacity to respond to the emergency."
Many of those afflicted with the disease have fled to neighboring countries to seek medical health -- which risks spreading the outbreak still further.
A group of former leaders known as The Elders expressed "bitter disappointment" in the Mugabe government Sunday, saying it cannot lead Zimbabwe out of its crisis.
The members of the group -- former U.N. Secretary General Kofi Annan, former U.S. President Jimmy Carter and human rights campaigner Graca Machel -- were denied entry to the country last month. They compiled a report based on meetings with Zimbabwean international experts in Johannesburg instead.
"We were expecting a gloomy situation, but the situation is far beyond what we could have imagined," said Machel, who is married to former South African President Nelson Mandela -- also a member of The Elders.
Nearly half Zimbabwe's population will need food aid by January, The Elders' report predicted.
Last week UK Prime Minister Gordon Brown branded the crisis "an international emergency."
Brown called on the international community to tell the 84-year-old Mugabe "enough is enough," and suggested that the U.N. Security Council meet to discuss the issue.
He said the most pressing issue was to ensure that testing and rehydration equipment and packs reach the right people, as well as for aid agencies to set up a organizational structure in the capital Harare to confront the disease.
"The people of Zimbabwe voted for a better future. It is our duty to support that aspiration," Brown added.
Brown's comments came one day after U.S. Secretary of State Condoleezza Rice said that the outbreak is the latest sign that Mugabe's rule over the country must end.
"It's well past time for Robert Mugabe to leave. I think that's now obvious," Rice said during a visit to Denmark.
Washington has long called for Mugabe to leave office, with President Bush calling Zimbabwe's runoff presidential election in June a "sham" and instructing Rice and other U.S. officials to develop additional sanctions against Mugabe's "illegitimate government."
"The United States will always do anything and everything that it can to help innocent people who are suffering," Rice said. "And we are not going to deny assistance to people in need because of their government. But if this is not evidence to the international community that it's time to stand up for what is right, I don't know what will be. And frankly, the nations of the region have to lead it."
The country, once a breadbasket of Africa, is also in the midst of an economic crisis, with its official rate of inflation at 231 million percent -- the world's highest.
Zimbabwe has had no Cabinet since the March presidential election. Mugabe's ruling ZANU-PF party has held on-again, off-again talks with the opposition led by Morgan Tsvangirai. Tsvangirai is Zimbabwe's prime minister under a power-sharing agreement negotiated by former South African President Thabo Mbeki.
Kenya's Odinga is himself a former opposition leader who came to office as part of a power-sharing agreement negotiated by former U.N. Secretary-General Kofi Annan.
Critics of Mugabe link hyperinflation to his policies on land distribution and unbudgeted payments to people who call themselves "war veterans," who have forcibly occupied white-owned farms.