REUTERS - Large numbers of civilians have been killed, raped or burned out of their homes in the latest upsurge of fighting in South Sudan, UN officials said on Monday.
"Military operations in Unity and Upper Nile states over the past three days in particular have again devastated countless lives," Toby Lanzer, the United Nations Humanitarian Coordinator for South Sudan, said in a statement.
"Eyewitness accounts report targeted rape and killing of civilians, including children," the statement said, without pointing to any one of the warring sides.
"I call on all commanding officers to ensure that their combatants protect and respect civilians, including national and international aid workers and their property."
He said the latest fighting had also left over 650,000 civilians without access to aid. In Unity state, thousands of homes had been burned and a hospital in the town of Leer was under threat of destruction.
The world's newest state, which declared independence from Sudan in 2011, was plunged into conflict nearly 18 months ago between forces loyal to President Salva Kiir and rebels allied with his former deputy, Riek Machar.
Several ceasefires have been agreed and broken and each side accuses the other of violating one announced in early February.
The conflict reopened ethnic fault lines between Kiir's Dinka people and Machar's forces, who are largely ethnic Nuer.
Rebel forces claimed to have inflicted serious losses on government forces in three days of fighting in Malakal, the capital of Upper Nile State.
The rebel forces brought down a helicopter gunship that had been sent to attack rebel positions on Sunday, rebel spokesman Lony Ngundeng told Reuters.
"The government forces have lost many soldiers," he said.
Government spokesmen were not immediately available to comment.
Lanzer said there had been fighting outside a UN civilian protection site in Malakal that led to civilian injuries.
IGAD, the regional group acting as mediator in the conflict, said the rebels had allied with the Shilluk militia of General Johnson Olony to attack the government's positions in and around Malakal.
It was not immediately clear if Olony, a major general in the government army, had officially defected to the rebel side. Ngundeng said the rebels and Olony's forces jointly controlled the town.
"The IGAD Mediation is deeply frustrated by the spread of violence to Upper Nile and strongly condemns this serious violation of the Cessation of Hostilities Agreement," the group said in a statement.
Malakal is the base for aid agencies in the state, where an estimated 245,000 people have been displaced by the conflict.
The UN Security Council on Sunday condemned the renewed fighting.