The US threatened to slash aid to South Sudan late on Wednesday, accusing its government of imposing “illicit costs” on humanitarian operations and hindering UN peacekeeping efforts.

“These actions constitute egregious violations of South Sudan’s international obligations,” a statement from the US State Department’s Bureau of African Affairs said, urging the transitional government to “halt these actions immediately.”

It warned that if the actions continued, the US would launch a comprehensive review of its assistance to Juba that could lead to “significant” cuts.

“South Sudan’s leaders deny any responsibility for the humanitarian crisis in their country while calling for ever-increasing donor funding. This is a false narrative,” it said.

South Sudan denies responsibility

The US said the transitional government should cooperate with those assisting its people, ensuring public revenue is used appropriately for salaries, health and education services, and support for those in need rather than obstructing aid efforts.

South Sudan, the world’s youngest nation, gained independence from Sudan in 2011 following a referendum.

However, it has remained mired in conflict since December 2013, when President Salva Kiir Mayardit dismissed and accused then-Vice President Riek Machar of plotting a coup.