JUBA - The United Nations says hundreds of people have been killed during recent tribal clashes and cattle raids in South Sudan. The UN said Monday that 600 people were “reportedly” killed in fighting between the Murle and Lou Nuer communities in Jonglei state. A statement said there were unconfirmed reports of more than 750 people being wounded. The UN representative in South Sudan, Hilde Johnson, said the cycle of violence must stop. South Sudan ended a two-decade civil war with Sudan in 2005. It officially became Africa's 54th nation last month. But the new country continues to struggle with internal violence, including cattle raids, a form of cultural and economic violence between tribes that is devastating communities.