The ongoing conflict in Yemen is having a devastating impact on the country's health system, and exposing millions of children to the threat of preventable diseases, says UNICEF.

"Children are not being vaccinated – either because health centres do not have electricity or the fuel they need to keep vaccines cold and distribute them, or because parents are too frightened by the fighting to take their children to receive vaccinations, "the UNICEF said in a statement.

"The tragic result is that children are going to die of diseases like measles and pneumonia that would normally be preventable."

According to UNICEF, the interruption in vaccination services is putting an estimated 2.6 million children aged under 15 at risk of contracting measles – a potentially fatal disease that spreads rapidly in times of conflict and population displacement.

The number of children exposed to Acute Respiratory Infections (ARIs) is likely to reach 1.3 million since the escalation of the conflict in March many hospitals and health centres are not functioning properly, making timely treatment increasingly difficult for parents to access.

Meanwhile, over 2.5 million children are at risk of diarrhea due to the unavailability of safe water, poor sanitary conditions and lack of access to Oral Rehydration Salt (ORS) -- compared to 1.5 million prior to the conflict.

Malnutrition is also posing a growing threat: UNICEF estimates that more than half a million children under five are at risk of developing severe and acute malnutrition over the next 12 months if the situation continues to deteriorate (as compared to 160,000 before the crisis). 1.2 million children under five are at risk of moderate acute malnutrition – a near two-fold increase from before the crisis.

At least 279 children have been killed and 402 injured as a direct result of the conflict which escalated in late March.