US President Barrack Obama says President Salva Kiir and Dr Riek Machar must sign a peace deal on the 17th of August.

Mr Obama says the international community must raise the cost of the actions of the two leaders if they fail to reach a peace deal.

He says accountability for atrocities committed in the conflict must be part of any lasting peace agreement.

Mr Obama made the remark in an address to the African Union in Addis Ababa this on Tuesday.

“In South Sudan, the joy of independence has descended into the despair of violence. I was there at the United Nations when we held up South Sudan as a promise of the new beginning,” Mr Obama stated.

“And neither Mr Kiir nor Mr Machar has shown so far an interest in sparing the people from the suffering or reaching a political solution.

“Yesterday [Monday], I met with leaders from this region. We agreed that given the current situation, Mr Kiir and Mr Machar must reach an agreement by August 17th, because if they do not, I believe the international community must raise the costs of intransigence.”

Negotiators of the two warring parties are expected in Addis Ababa in the first week of next month to continue negotiating an end to the violence.

They will be discussing a proposal by mediators under a new initiative known as IGAD-Plus.

The international mediators have proposed demilitarization of Juba and the reintegration of forces within a year during the transitional period.

Under the proposal, President Salva Kiir would remain in office and Dr Riek Machar becomes the First Vice President.

On power sharing, it says the government would take 53 percent of the national ministerial positions, 33 for the SPLM in Opposition and 14 for the former detainees and other political parties.

In the Upper Nile region, the SPLM-IO would take 53 percent, 33 for the government and 14 for the former political detainees and other political parties.

The warring parties will respond to the proposal and discuss the issues before the deadline.

But many agreements signed after the outbreak of the conflict in 2013 have not been fully implemented.