More than half a million cholera cases in Yemen
The highly contagious disease is treatable, but the collapse of Yemen's infrastructure following more than two years of a Saudi-led war against Houthi rebels in the country has created a "perfect storm for cholera", the WHO has said.
More than a quarter of the deaths and over 41 percent of all suspected cases are children.
WHO warned that the disease had spread rapidly due to deteriorating hygiene and sanitation conditions, with millions of people cut off from clean water across the country.
"Yemen's health workers are operating in impossible conditions," WHO chief Tedros Adhanom Ghebreyesus said in a statement.
"Thousands of people are sick, but there are not enough hospitals, not enough medicines, not enough clean water," he said, also lamenting that many of the doctors and nurses needed to rein in the outbreak had not been paid for nearly a year.
"They must be paid their wages so that they can continue to save lives," he said.
WHO said that it is working with its partners around the clock to support national efforts to halt the outbreak, adding that 99 percent of people who contract cholera can survive with access to health services.
"The people of Yemen cannot bear it much longer - they need peace to rebuild their lives and their country," he said.
The war in Yemen has left more than 10,000 dead since it escalated with the Saudi-led coalition intervention in March 2015.