In just five months the number of people without access to safe drinking water in Ethiopia, Kenya and Somalia has risen from 9.5 million to 16.2 million, the United Nations Children's Fund (UNICEF) warned in a statement this Tuesday.

The UN agency also says that the humanitarian emergency also affects children in the Sahel region.

"Children in the Horn of Africa and the Sahel could die in very high numbers if urgent assistance is not provided at a time when severe malnutrition and the risk of waterborne diseases overlap," warns Unicef, which releases the statement on World Water Week.

Previous data shows that when high levels of severe acute malnutrition in children occur at the same time as outbreaks of deadly diseases such as cholera or diarrhea, child mortality increases dramatically and tragically. "When water is unavailable or unsafe, the risks to children multiply exponentially," says Unicef Executive Director Catherine Russell, quoted in the note.

"In the Horn of Africa and the Sahel, millions of children are only a disease away from disaster," continues Catherine Russel.

In Burkina Faso, Chad, Mali, Niger and Nigeria, drought, armed conflict and instability "are leading to insecure access to water, with 40 million children facing high to extremely high levels of water vulnerability.

"According to the latest WHO [World Health Organization] data, more children are already dying as a result of unsafe water and sanitation in the Sahel than anywhere else in the world," the statement read.

The note also points out that more than 2.8 million children in the two regions Horn of Africa and Sahel, "already suffer from severe acute malnutrition, which means that they are up to 11 times more at risk of death from waterborne diseases than well-nourished children," the note concludes.