Three aid workers killed as S Sudan clashes leave 'many' dead

South Sudan's UN peacekeeping mission said Wednesday it was investigating reports that "many people" had died in a surge of intercommunal violence that killed three aid workers and left several missing.

Clashes between members of the Murle and Lou Nuer communities broke out over the weekend in the northeastern town of Pieri, where peacekeepers have been interviewing survivors, the UN mission said in a statement.

"The team is investigating reports that many people were killed, injured and lost their homes," the statement said, adding that "many" huts were burnt to the ground.

"However, it is difficult to verify the number of casualties given conflicting reports and claims," it said. Moses Majok Gatluak, a member of the Lou Nuer group and former local official in the area, told AFP that 211 people were killed and 300 injured, but that toll could not be independently verified.

He said the Murle had attacked Lou Nuer villages. The attack comes after a strike by the Lou Nuer against the Murle earlier this year - part of a decades-old pendulum swing of violence and revenge by the two cattle-rustling communities.

The fighting often leaves hundreds dead, with one attack in 2009 killing up to 750, according to the UN.

"These violent assaults on civilian communities as part of an ongoing cycle of revenge must stop," said David Shearer, the UN's special representative for South Sudan.

"While politically motivated conflict has reduced in South Sudan, intercommunal fighting has increased, causing massive suffering for families who are trying to rebuild their lives after the devastation caused by years of civil war," Shearer said. South Sudan is emerging from a brutal six-year civil war that left 380,000 dead and millions displaced.

President Salva Kiir and Riek Machar, the rebel leader who is now first vice president, reached a deal to form a unity government in February but remain at odds over issues including who will govern the country's 10 internal states.

The UN said "some of the violence" in and around Pieri could be attributed to the "vacuum of power" resulting from the deadlock over local governance.