Clashes between rival regiments of the South Sudan army have left over 500 people dead and prompted fears of a coup in Africa’s newest nation.

Reports from church leaders in South Sudan report gunfire and clashes in the capital of Juba and in the town of Bor in Jonglei State. Nineteen civilians have been killed in the fighting in Bor the South Sudan Red Cross reports, while several hundred soldiers have been reported killed in clashes across the country.

The United States has ordered its citizens to leave South Sudan immediately, and a dusk to dawn curfew is in place in Juba.

Initial reports from South Sudan state the fighting has pitted soldiers from the Dinka tribe of President Salva Kiir against soldiers from the Nuer tribe of former Vice President Riek Machar. In July President Kiir sacked his vice-president sparking a political crisis that may now have turned bloody.

In a BBC interview Wednesday, Dr. Machar denied he had led a coup attempt, and blamed the fighting on a conflict between members of the presidential guard. He added that government troops used the incident to arrest some of his supporters Monday and that he himself escaped.

U.N. chief Ban Ki-moon told reporters on 18 Dec 2013 South Sudan was in the throes of a crisis that “urgently needs to be dealt with through political dialogue.” He urged President Kiir “to resume dialogue with the political opposition.”

In an email sent to supporters in the New Wineskins Network, the Rt. Rev. Abraham Nhial, Bishop of Aweill, wrote that President Kiir had announced on television that a group led by Dr. Machar had attempted a “coup but they failed. Also, many of our politicians are now been arrested in Juba.”

“I am not sure how true the President announces is true because politicians are politicians but what I know the President and former Vice President have political differences.”

The bishop added: “As I am sending you this email to pray for us, we already lost 12 people, more then 130 people are wounded, many are still missing and many people are been displaced. No one believe what has happened in South Sudan because South Sudan is a nation just came out from the longest suffering but our politicians are already forgotten what we went through, very sad.”

“Please keep us in your thoughts and prayers, so that we can celebrate the birth of Jesus Christ peacefully. God bless you all.”