Harare: The United States said on Friday that President Robert Mugabe's departure from office was long overdue and a food crisis and cholera epidemic in Zimbabwe meant it was now vital for the international community to act.

Zimbabwe has declared a national emergency and appealed for international help to battle a cholera outbreak that has killed 575 people with 12,700 reported cases of the disease, according to the United Nations.

"It's well past time for Robert Mugabe to leave," U.S. Secretary of State Condoleezza Rice said in Copenhagen.

Nobel laureate and South Africa's Archbishop Desmond Tutu said on Thursday that Mugabe must step down or be removed by force and that the Zimbabwean leader faced indictment for war crimes in the Hague unless he quit.

Rice said stalled power-sharing talks, a "sham election" earlier this year, economic meltdown and the humanitarian toll from the cholera epidemic required swift action.

"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," Rice told a news conference, adding: "... frankly the nations of the region have to lead it."

Economic meltdown in Zimbabwe, isolated by Western countries under Mugabe's increasingly authoritarian rule, has left the health system ill-prepared to cope with the cholera epidemic that it once would have prevented or treated easily.

The country has the highest official modern-day inflation of 231 million percent but inflation is seen much higher with prices doubling every 24 hours. Basic foods are often unobtainable and the currency worthless.

Source : Reuters