South Africa's Red Cross is rushing much-needed medicine to Zimbabwe
The United Nations says 978 people have now been killed by the cholera outbreak in Zimbabwe, an increase of 25% from the last figure given three days ago.
Another 18,413 suspected cases have been reported since August, the report said ahead of the UN Security Council's first talks on Zimbabwe since July.
The talks ended without agreement on a motion to censure Zimbabwean President Robert Mugabe.
Separately, Botswana denied plotting to overthrow Zimbabwe's president.
The UN's Office for the Co-ordination of Humanitarian Affairs (Ocha) said the worst-hit area was the capital, Harare, with 208 confirmed deaths and 8,454 suspected cases.
The South African Red Cross has sent much-needed medical supplies to Zimbabwe, and has issued an appeal for funds to treat a total of 30,000 people.
The UN has warned that up to 60,000 people could become infected if the outbreak is not contained.
The Ocha's revised death figures were released hours before the UN Security Council met for its first discussions on Zimbabwe since it failed to pass new sanctions on the country's leaders in July.
David Miliband: 'We heard a devastating report from the secretary general'
The meeting was designed, as UK Foreign Secretary David Miliband put it, to "restart UN engagement on this issue".
But a motion to censure Mr Mugabe was blocked by opposition from South Africa.
Speaking to reporters after the Security Council's discussions, Mr Miliband said the council had heard a "devastating report" from UN Secretary General Ban Ki-moon about "the disintegration of state institutions, the collapse of the economy, the disembowelling of the economic institutions, [and] the collapse of health and education services" in Zimbabwe.
"And of course, the symptom of that disintegration is the shocking fact that cholera has returned to Zimbabwe" and was spilling over into neighbouring states, Mr Miliband said.
The Security Council also heard a briefing on the stalled power-sharing agreement between President Robert Mugabe and opposition leader Morgan Tsvangirai.
The rivals agreed to form a power-sharing government in September but its implementation has been dogged by disagreements over whose supporters would get key ministries.
The political crisis has aggravated an ongoing economic meltdown that has brought Zimbabwe the world's highest inflation rate.
In the southern town of Beitbridge, which borders South Africa, 91 people have died from cholera while several more thousand people are believed to be infected.
'Pretext to invade'
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."
Now that there is no cholera, there is no cause for war
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