After the United Nations World Food Program (WFP) received the Nobel Peace Prize on Friday, the U.S. State Department is calling for South Sudan to investigate and provide security for the WFP after an attack this week.
"We call on the Government of South Sudan to investigate this attack fully and expeditiously and provide the security necessary to ensure the safety of aid workers who are delivering critical life-saving services and assistance," State spokeswoman Morgan Ortagus wrote in a statement.
An aid worker remains missing and three are injured after the second attack on humanitarian cargo vessels in that area in the past two months, the statement noted.
"The United States is deeply concerned by the attack on a United Nations World Food Program (WFP) humanitarian cargo convoy in South Sudan this week," it read.
"We express our sympathy to the family of the missing aid worker and wish the wounded a full and swift recovery," it continued.
"Humanitarian aid workers in South Sudan and throughout the region work under extremely challenging conditions to assist some of the world's most vulnerable men, women, and children."