The United States on Friday expressed "deep concern" about reports of killings, beatings and looting in South Sudan's eastern state of Jonglei and said the military had a responsibility to protect all civilians.
"We urge all parties - including the Sudan People's Liberation Army (SPLA) and other state and non-state armed actors - to end the violence, and to work toward peace and reconciliation through dialogue," the State Department said in a statement.
In New York, U.N. spokesman Martin Nesirky urged national and state authorities to exercise "maximum restraint."
Fighting between South Sudanese troops and armed groups in Jonglei has forced tens of thousands of people to flee their homes. A U.N. mission has fewer than 6,900 peacekeepers to cover a country the size of France.
Nesirky said the U.N. Mission in South Sudan (UNMISS) was "deeply concerned" about reports of a major mobilization of armed youths moving toward Pibor county in Jonglei state, as well as reported clashes.
He said the United Nations was trying to gain access to the area to verify the reports of violence. "UNMISS is trying to verify the information and assess population movements, including through the use of aerial reconnaissance flights," he said.
"Its mobility continues to be hampered by inadequate air assets, which severely limit its capability to detect violence in inaccessible rural areas," Nesirky added.
The State Department urged all parties to provide "unfettered" humanitarian access to all areas of Jonglei and to allow U.N. peacekeepers to conduct patrols.