Secretary-General Ban Ki-moon is alarmed at the desperate humanitarian situation in Zimbabwe and is urging all countries to provide aid, leaving political considerations aside.

Ban is also calling on Zimbabwe's President Robert Mugabe and opposition leader Morgan Tsvangirai to reach a fair and workable power-sharing agreement at talks in South Africa.

U.N. spokeswoman Michele Montas said Tuesday the secretary-general believes the people of Zimbabwe cannot afford another failure by their political leadership to reach an agreement.

The U.N. says more than 5 million people face imminent starvation in Zimbabwe, where the number of cholera cases is rising.