HARARE, Zimbabwe (CNN) -- The Zimbabwean government has declared a national emergency in the face of a cholera outbreak that has killed more than 560 people, the state-owned newspaper The Herald said Thursday.

A shortage of clean drinking water has unleashed a cholera epidemic in Zimbabwe.

Harare also appealed for help for its hospitals, which Health Minister David Parirenyatwa said "are literally not functioning."

"Our staff is demotivated and we need your support to ensure that they start coming to work and our health system is revived," he said at a meeting of donors including United Nations agencies, embassies and non-governmental institutions, The Herald reported.

Cholera cases are on the increase in nine of Zimbabwe's 10 provinces, the U.N. Office for the Coordination of Humanitarian Affairs (OCHA) warned Wednesday. It blamed "poor water and sanitation supply, a collapsed health system and limited government capacity to respond to the emergency."

OCHA said the water-borne outbreak had killed at least 565 people and sickened more than 11,000. See more about Zimbabwe's cholera crisis »

In Harare province, more than one in four people to contract the disease had died and there were nearly 7,000 new cases, OCHA said.

The health crisis is taking place against a background of increased security in the face of expected runs on banks.

Armored cars patrolled the streets of Zimbabwe's capital and residents flocked to banks Thursday after limits on cash withdrawals were lifted in the inflation-ravaged African nation.

The Reserve Bank of Zimbabwe had capped maximum daily withdrawals at 500,000 Zimbabwean dollars -- about 25 U.S. cents, and about a quarter of the price of a loaf of bread. But faced with mounting chaos in a country already in economic free fall, the bank decided last week to raise that limit to 100 million dollars ($50 U.S.) per week.

Soldiers were deployed to all banks in anticipation of throngs of people lining up to withdraw money Thursday, when the increase took effect. Wednesday, police chased depositors away and arrested union leaders who planned to protest the limits.

Zimbabwe's inflation rate of 231 million percent is the world's highest.

The Zimbabwe Congress of Trade Unions said 69 people were arrested across the country during Wednesday's demonstrations. Amnesty International has demanded to know the whereabouts of human rights activist Jestina Mukoko. The group said Mukoko was abducted at dawn Wednesday by armed men in plainclothes posing as police.

And angry, unpaid soldiers clashed with foreign currency exchangers and some civilians Monday, three days after troops who had failed to get cash from their banks looted shops they suspected to be illegally dealing in foreign currency.

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