Fears of civil war drive leaders to South Sudan to talk peace Leaders from Kenya and Ethiopia are in Juba to talk about peace The bloodshed is a tribal conflict that mirrors one in 1991 Four U.S. Navy SEALS were wounded by rebels on Saturday Bor, South Sudan (CNN) -- Fears that a new civil war could erupt in South Sudan drove leaders of two neighboring African countries into its capital Thursday. Kenya President Uhuru Kenyatta and Ethiopia's Premier Hailemariam Dessalegn landed in Juba to talk about peace with a head of state who is at war. South Sudan's President Salva Kiir is fighting a rebellion led by his former Vice President, whom he dismissed months ago. It's not the first time Riek Machar has broken rank and turned against his former allies. A bloodletting on Wednesday in the South Sudan city of Bor, was a real-time repeat of slaughters 22 years before. Recurring nightmare In 1991, when the south still belonged to the nation of Sudan, it fought a bloody civil war against the north. Machar had a falling out with John Garang, who led the fight against the north. They are again fleeing government troops battling rebel followers of Machar. Even they ran to save their own lives. President Kiir's soldiers were in control. The conflict, which broke out mid-month has led to mass killings as evidenced by mass graves, the United Nations has said. It's a tribal war, in which ethnic interest is placed above national unity. Kiir and Machar are longtime rivals from two different tribal clans -- Kiir, like Garang before him, is from the Dinka tribe, and Machar from the Neur. Upping U.N. troops The U.N. Security Council voted to add thousands more troops to its peacekeeping presence there to protect civilians in the young nation convulsed by violence. "I once again call on the country's leaders to settle their differences peacefully -- and I underscore their responsibility to protect civilians," Ban said. The Peace and Security Council of the African Union expressed "deep dismay and disappointment that the continent's newest nation should descend so rapidly into internal strife." In the last 10 days, 90,000 people have been forced from their homes; 58,000 of them are at U.N. peacekeeping bases. Wounded U.S. Navy SEALS READ: South Sudan: What's going on? READ: In South Sudan city, victims of violence reliving memories READ: 'Peace on Earth' means Syria, Sudan, and Nigeria, Pope says on Christmas