The United States has condemned an armed attack on World Food Programme workers and the looting of humanitarian assistance in Chuilbong, Jonglei State, South Sudan.

In a statement on Monday, the U.S. said the looted aid was meant to feed nearly 20,000 people in need, describing the assault as another example of armed actors preying on humanitarian assistance at the expense of the country’s most vulnerable people.

“Humanitarian workers must never be targets. We call on South Sudan’s leaders and all parties to guarantee safe and unimpeded humanitarian access, prevent further attacks, and hold everyone responsible for such appalling attacks to account. The humanitarian crisis in South Sudan is manmade,” the statement said.

The U.S. urged the country’s leaders to use public revenue to provide basic services for their people.

The latest attack followed several attacks on agencies and non-governmental organisations providing humanitarian assistance amid escalating violence, political collapse and widespread intercommunal clashes in the country.