"We see a great risk for the start of an epidemic, as the population has limited access to food and drinking water. An outbreak of cholera and respiratory infections is quite possible," said the WHO's Melanie Zipperer.

"The hospitals in Baghdad are completely overflowing and could run low on medication or medical equipment. If the situation gets worse, we will have to face a humanitarian crisis," Zipperer told French news channel LCI.

She said the WHO had asked that a corridor be opened to funnel aid to the Iraqi people. She said the organization had supplies stored in Jordan, Kuwait, Syria and Turkey but emphasized that access was nearly nonexistent.

Cholera is a water-borne illness characterized by diarrhea, vomiting, muscle cramps and severe loss of body fluids, and tends to crop up when sanitation is poor. It can be fatal if not properly treated.

SPACE.WIRE