(CNN) -- The number of cholera deaths in Zimbabwe is approaching 1,000, according to U.N. figures published Monday.
Two Zimbabweans rest in a cholera rehydration tent on the South Africa-Zimbabwe border.
The U.N. Office for the Coordination of Humanitarian Affairs said 978 people have died and 18,413 suspected cases have been recorded.
U.N. figures have been compiled since August.
The latest death toll is reported amid claims by one of Zimbabwe's top officials blaming the cholera outbreak on "a genocidal onslaught" by Zimbabwe's former colonial ruler -- Britain.
"Cholera is a calculated, racist attack on Zimbabwe by the unrepentant former colonial power, which has enlisted support from its American and Western allies so that they can invade the country," Information Minister Sikhanyiso Ndlovu told reporters.
Britain ruled the country as a colony until 1965.
Ndlovu's claims triggered quick and pointed reaction from Britain and the United States.
In Washington, State Department spokesman Rob McInturff called Ndlovu's accusations "patently ridiculous."
Referring to Zimbabwean President Robert Mugabe, McInturff said Friday that, "Mugabe is clearly unwilling to take any meaningful action (to stop the cholera outbreak)."
On Thursday, Mugabe said "there is no cholera in the country." His spokesman later said that Mugabe was sarcastically ridiculing what he believes are Western designs to invade the country.
Britain's Africa minister, Mark Malloch-Brown responded by saying, "I don't know what world he (Mugabe) is living in," according to the British newspaper The Guardian.
Malloch-Brown made the comment during a one-day trip to South Africa, where he visited a Johannesburg church housing 1,600 Zimbabweans who have fled their country, the newspaper said.
"There is a raging humanitarian crisis in Zimbabwe as well as an economic crisis and still there is no representative government able to lead the country out of this disaster," he said, according to The Guardian.
The outbreak, which has already killed nearly 1,000, could surpass 60 000 cases, according to an estimate by the Zimbabwe Health Cluster, which is a group coordinated by the World Health Organization. View image gallery of Zimbabwe's cholera crisis »
Cholera, a bacterial waterborne disease that causes diarrhea, dehydration and, if not treated, death in a matter of hours, is widespread in Zimbabwe but help is not.
Like the general Zimbabwean economy, the country's health delivery system is strapped, lacking modern drugs and machinery, while doctors and nurses have been striking for over a month.
On Friday, the State Department issued a travel warning for U.S. citizens because of the cholera outbreak and violence that has flared as Zimbabwe's economy has deteriorated.
"The public health system in Zimbabwe no longer provides even basic services due to a lack of staff, electricity, clean water, and medical supplies," the travel warning said. "Americans who fall ill while in Zimbabwe may find it difficult to find treatment."
At the State Department's daily press briefing Friday, spokesman Sean McCormack said the situation in Zimbabwe will be one of the topics Secretary of State Condoleezza Rice will discuss when she visits the United Nations next week.
"The number of cases of cholera -- statements from Robert Mugabe notwithstanding -- is going up, not down," McCormack said. "The crisis has not ended. People's lives are in danger."
Health experts say the Zimbabwean government can win the battle against cholera only if it imports adequate stocks of water-treating chemicals and disposes of refuse and sewerage properly.
A Doctors Without Borders epidemiologist in Zimbabwe said, referring to the capital city, that "the scale and sheer numbers of infection, especially in Harare, is unprecedented." He said the group has treated more than 11,000 patients since August and has 500 international and local staff members treating people in cholera centers across the country.
He said the main reasons for the outbreak are poor access to clean water, uncollected garbage in the streets and burst and blocked sewage systems.
"The fact that the outbreak has become so large is an indication that the country's health system can't cope," he said.
Meanwhile, in his statement Thursday Mugabe said, "I am happy to say our doctors, assisted by others and the World Health Organization, have now arrested cholera. So now that there is no cholera, there is no cause for war anymore. Let's tell them (Britain and the United States) that the cholera cause does not exist anymore, if it was cause for war."
The pro-government Herald, quoting presidential spokesman George Charamba, said Mugabe had been sarcastically reacting to "calls for intrusive action" against Zimbabwe from European leaders.
Charamba said the country continues to want international assistance to combat the disease and has declared a state of emergency.
The opposition Movement for Democratic Change, which rivals Mugabe's ZANU-PF party, issued statements deploring the Mugabe government's "indifferent and casual approach" to cholera and saying it was "alarmed by Mugabe's irresponsible and false remarks" on Thursday.
"The ZANU-PF caretaker government is in a denial mode. The MDC believes that it is such careless and reckless statements that have not helped the situation," MDC said.
"We should be honest with ourselves and with the world. The truth is that cholera remains a major disaster in Zimbabwe," the MDC said.
In his remarks to reporters in Zimbabwe, Ndlovu -- who said the country's health system is working on the outbreak -- labeled the cholera outbreak "a serious biological, chemical war force, a genocidal onslaught, on the people of Zimbabwe by the British,"
He also made reference to U.S. President George W. Bush and Rice: "To the outgoing warmongers, please leave in peace and not in pieces."
Ndlovu also slammed news outlets including CNN for what he called "gunboat journalism."
"They take photos (of) people dying (in) the DRC and Darfur and say these are cholera victims from Zimbabwe," he said, making reference to the Democratic Republic of Congo and the Darfur region of Sudan.