A state of emergency has been declared in the Yemeni capital, Sanaa, after an outbreak of cholera killed scores of people.
Hospitals in the city, which is controlled by Houthi rebels, are crowded with cholera patients.
The Red Cross says the number of suspected cases in the country has tripled in a week to more than 8,500.
Yemen has been ravaged by hunger and civil war, allowing disease to spread rapidly.
Two-thirds of the population do not have access to safe drinking water, according to the UN.