Gunmen Storm S.Sudan U.N. Base, Wound Dozens of Civilians

Gunmen stormed a U.N. base in South Sudan Thursday, wounding dozens of civilians from a rival tribe in an "unprovoked" attack before peacekeepers fought them off, the U.N. said.

The top U.N. aid official in South Sudan, Toby Lanzer, said he was "outraged" by the assault in the war-ravaged town of Bor, in which two peacekeepers were also wounded.

Almost 5,000 civilians are sheltering inside the fortified base of the United Nations Mission in South Sudan (UNMISS), one of the most bitterly contested regions in the four-month-long conflict splitting the country.

UNMISS condemned "heinous murders" in the attack, although it has not officially confirmed any deaths.

"The armed mob forced entry into the site and opened fire on the internally displaced persons sheltering inside the base," the UNMISS said in a statement, saying its forces returned fire -- first firing warning shots and then taking part in a ferocious gun battle -- before the fighters retreated.

The gunmen had initially approached the camp "under the guise of peaceful demonstrators" intending to present a petition to the U.N., before opening fire and breaching the compound, the statement added.

The civilians fled into the base weeks ago amid brutal ethnic massacres in the world's newest nation.

Information Minister Michael Makuei said that a "huge number" of gunmen had come seeking revenge for the rebel capture of the oil town of Bentiu two days ago hoping to kill the trapped civilians, many of them children.

The conflict in South Sudan has left thousands dead and forced around a million people to flee their homes since fighting broke out on December 15 in the capital Juba before spreading to other states in the oil-rich nation.

Bor, the capital of Jonglei state, has swapped hands several times during the conflict.

The latest clashes in Bor echo an attack by gunmen in December on a U.N. base in Akobo, also in Jonglei, killing at least 11 civilians and two Indian U.N. peacekeepers.

More than 67,000 civilians across the country are sheltering inside U.N. bases for protection from ethnic attacks, with heavy fighting ongoing as the rebels say they are targeting key oil fields.

On Thursday, the army said it was trying to wrest back control of Bentiu from fighters loyal to rebel chief Riek Machar.

"Bentiu is still under the hands of the rebels but we are closing in," army spokesman Philip Aguer told Agence France Presse. "There is still fighting."

Information Minister Makuei insisted all oil fields were under government control, but that production had stalled in Unity -- a key oil zone -- as facilities were damaged in fighting.

U.N. peacekeepers reported dozens of corpses littering the streets of Bentiu, the state capital of Unity, which rebels had previously seized in December at the beginning of the conflict.

The fighting is between soldiers loyal to President Salva Kiir and mutinous troops who have sided with his former vice president Machar, whom Kiir sacked in 2013.

The conflict has taken on an ethnic dimension, pitting Kiir's Dinka tribe against militia forces from Machar's Nuer.

U.N. Secretary General Ban Ki-moon has warned that more than one million people are at risk of famine in the troubled country.

More than 3.7 million people are in dire need of food aid, many of them being forced to eat "famine foods" such as grasses and leaves, U.N. children's agency UNICEF said Thursday.

"Worse is yet to come," said UNICEF chief in South Sudan Jonathan Veitch in a statement.

"If conflict continues, and farmers miss the planting season, we will see child malnutrition on a scale never before experienced here."