The country's capital Harare is the worst-hit district, with 208 deaths and 8,454 suspected cases, the UN Office for the Co-ordination of Humanitarian Affairs said.
Beitbridge, which border South Africa, was also badly affected. Some 91 people in the border town have been killed by the disease, while 3,546 are suspected to be suffering from it.
The latest toll came even as the United States and Britain were expected to lobby the UN Security Council to turn up the heat on Zimbabwean President Robert Mugabe.
But Harare has vowed to thwart western efforts to put Zimbabwe on the Security Council agenda, saying it was not a threat to international security.
The South African Red Cross has sent medical supplies to Zimbabwe, and has issued an appeal for funds to treat a total of 30,000 people.
The UN has said it estimates up to 60,000 people may eventually be affected.
On Thursday, Mr Mugabe gave a nationally televised speech saying the outbreak had been contained.
"I am happy to say our doctors are being assisted by others, and the WHO [World Health Organization] have now arrested cholera."
He has accused Western powers, including Zimbabwe's former colonial ruler Britain, of using the cholera outbreak as a pretext to invade the country and overthrow him.
"Now that there is no cholera, there is no cause for war," he said.
Other high-ranking officials have accused Britain of deliberately spreading cholera.
In a separate development, neighbouring Botswana has denied a Zimbabwean accusation that it was involved in a plot to overthrow Robert Mugabe's government.
President Mugabe declared that the cholera outbreak has been contained
The United Nations has reported that a total of 978 people have been killed by a cholera epidemic in the African nation of Zimbabwe, an increase of 25% from just three days ago. The UN also says that there have been 18,413 reported cases in the country since the epidemic began in August of 2008.

The outbreak of the disease has been quickened by the lack of proper sanitation and the collapse of water systems and healthcare. The area worst affected by cholera is Zimbabwe's capital of Harare, where 208 people died out of 8,454 suspected cases. The town of Beitbridge, which is located on the border with South Africa, has also been hard hit, with 3,546 cases reported and 91 people dead.

The South African Red Cross has sent medical aid to Zimbabwe, and has asked for funds to treat thirty thousand people. The UN says that as many as sixty thousand people could become affected by the disease if no action is taken.

Last Thursday, Zimbabwean president Robert Mugabe announced in a televised address that the outbreak had been halted, saying that "I am happy to say our doctors are being assisted by others, and the w:World Health Organisation|WHO World Health Organization have now arrested cholera."

Mugabe has also accused Western powers of plotting to use the epidemic as a reason to overthrow him. "Now that there is no cholera, there is no cause for war," he stated. Other Zimbabwean high-ranking officials have also blamed the United Kingdom for spreading cholera on purpose.

The UN Security Council will have a briefing on the Zimabwean cholera crisis soon.