South Sudan's government said 15 young children have died after a botched vaccination campaign that saw one syringe used for all children.

Health officials blamed the deaths on human error as people as young as 12 administered the measles vaccination which was also reportedly stored incorrectly.

The government said all of the children who died were under the age of five.

An investigation is being launched to determine who is responsible and whether victims' families will be compensated.

The measles vaccination campaign is targeting more than two million children across the country.