IGAD faults both the goverment of South Sudan and rebels loyal to Riek Machar for delaying implementation of the peace deal that was signed in August.
The United States says the meeting was cancelled because the two sides in South Sudan's conflict have shown complete disregard for the weeks'-old peace deal.
Mr. Kiir says he aims to silence all the "doubting Thomases" who don't believe there will be peace in South Sudan, and blames the opposition under Riek Machar for several breaches of a month-old ceasefire.
The United States pledges an additional $80 million to help internally displaced persons, victims of gender-based violence, children suffering from malnutrition and others affected by 20 months of violence in South Sudan.
Agreement aims to end nearly 20 months of fighting between government forces, rebels led by his former deputy
Journalists down tools for 24 hours and join the international community in calling on President Salva Kiir to explain a threat he made this week against the media, and find whoever killed reporter Peter Moi.
Government officials also say they are recalling their negotiating team from Addis Ababa, but lead negotiator Nhial Deng Nhial says he and his team are still at the talks and working towards reaching a peace deal.
After nearly a week of talks in Addis Ababa, the warring sides in South Sudan say disagreement on a number of key points is barring the way to peace.
Government and opposition negotiators come up with opposing proposals for power-sharing that bear no resemblance to what mediators put forward in a compromise deal.
The lead negotiators for the government and main armed opposition group kick off the new round of talks with fighting words, indicating that the path to signing a final peace deal by August 17 will be a bumpy one.
But the African Union Peace and Security Council only releases the report to government officials, drawing the ire of Riek Machar's rebel group, which has demanded that it be given a copy.
As the expanded mediation team, IGAD Plus, debates a compromise peace deal for South Sudan, a spokesman for the government of President Salva Kiir warns that his side will not sign the agreement if any new conditions are added to it.
IGAD says in a letter to South Sudanese negotiators that it has come up with a compromise deal to restore peace in South Sudan, and that the final deal will be signed on August 17 at an IGAD Plus summit.
Hundreds celebrate South Sudan's fourth birthday in Juba even as fighting continues to rage in other parts of the country.
The organizers say the inaugural tournament, held in memory of the 7-foot 7-inches NBA center, who died five years ago in June, has a broader message than just hoops.
For the second year in a row, South Sudan beats Somalia into second place on the Fragile States Index, compiled by U.S. research group, the Fund for Peace.
U.S. Special Envoy for Sudan and South Sudan says an IGAD proposal to have more mediators at the South Sudan negotiating table was endorsed at the African Union summit in Johannesburg.
Juba optimistic that new format for peace talks will lead to success, but analyst says roadblocks to settlement might be too many
Security Council members say the South Sudan government's announcement that it is expelling U.N. Humanitarian Coordinator Toby Lanzer shows "a disregard for the plight of the South Sudanese people."