JUBA, Aug. 13 (Xinhua) -- The Intergovernmental Authority on Development (IGAD) on Friday urged rival opposition factions in South Sudan to cease hostilities and abide by the 2018 revitalized peace deal.

During a meeting with First Vice President and leader of Sudan People's Liberation Movement/Army-in Opposition (SPLM/A-IO) Riek Machar, Workneh Gebeyehu, executive secretary of IGAD, urged rival factions to embrace dialogue.

"We encourage this thing (conflict) be resolved internally, that will be the best way to solve this issue, if not it could have spillover effect on the peace process," Gebeyehu said at a briefing in Juba, capital of South Sudan.

The regional bloc, which groups Djibouti, Ethiopia, Somalia, Eritrea, Sudan, South Sudan, Kenya and Uganda, mediated the 2018 revitalized peace deal signed in Ethiopia by South Sudanese warring parties to end more than six years of civil strife.

Gebeyehu said he will hold a discussion with the breakaway SPLM/A-IO faction led by Machar's former chief of staff Simon Gatwech Dual who is holed up in the Magenis area near the Sudan border.

The two factions clashed last week at Magenis leaving 34 soldiers dead.

The fighting followed the recent declaration by senior officers of SPLA-IO led by Dual deposing Machar from the leadership of SPLM/A-IO while accusing him of nepotism and lacking strong leadership.

The breakaway faction also blamed the First Vice President in the transitional unity government formed in February last year for weakening the hand of the former rebel movement in the coalition government.

Gebeyehu said the region is wary of further violence weakening the ongoing peace process whose slow implementation especially on security arrangement is one of the main grievances among members of the breakaway faction.

South Sudan is supposed to graduate 83,000 unified forces comprising of police, army, intelligence and wildlife but this continues to delay despite assurances by President Salva Kiir.

These forces upon graduation are supposed to take charge of security during the ongoing transitional period.

"The progress is very slow in the implementation of security arrangement, we express our concern for the leadership, for the President, for the First Vice President that security arrangement implementation phase is not going as planned that is really a challenge that South Sudanese are facing now," said Gebeyehu. - Xinhua