Authorities in Sanaa, which is controlled by Shiite rebels, have declared a state of emergency in the Yemeni capital, where a deadly outbreak of cholera has spread rapidly.
The Huthi-run health ministry said it was "unable to contain this disaster" and appealed for international humanitarian assistance to deal with the crisis, in a statement released overnight.
Yemen is witnessing a devastating war between the Iranian-backed Huthis and the Saudi-supported government, and less than half of the country's health facilities are functioning two years into the conflict.
The International Committee of the Red Cross said on Sunday the cholera outbreak has killed 115 people and left 8,500 ill between April 27 and Saturday.
This is the second outbreak of cholera in less than a year in Yemen, the Arab world's poorest country.
The World Health Organization now classifies Yemen as one of the worst humanitarian emergencies in the world alongside Syria, South Sudan, Nigeria and Iraq.