IGAD Chairman and Ethiopian Prime Minister Hailemariam Desalegn said he would encourage Kiir to attend the talks as he promised in a Feb. 1 agreement, Seyoum told reporters. “To resolve the outstanding issues between the two warring parties his attendance is very crucial,” he said.

Violence erupted in South Sudan in December 2013, when a power struggle within the ruling party turned violent and took on an ethnic dimension as the fighting spread. Tens of thousands of people have been killed and more than two million fled their homes because of the clashes.

Kiir has other duties that make it impractical to attend all of the negotiations, South Sudan Information Minister Michael Makuei Lueth said. “Whatever issue that is outstanding we will call him and he will come and address it and go back,” Lueth said in an interview on Monday in Addis Ababa.

Concern, Distress

Machar is in the Ethiopian capital waiting for the president to arrive and the power-sharing talks to resume, said Puot Kang Chol, a spokesman for the rebel delegation. “We are dismayed and we feel Salva must be reneging from what has been signed,” he said in an interview on Monday at the ceremony.

The U.K., U.S. and Norway, nations which are supporting the mediation, have “deep concern and regret” about Kiir’s absence, said Matthew Connell, the U.K.’s special representative to Sudan and South Sudan. The United Nations Security Council may consider a resolution this week that could result in sanctions being placed on South Sudanese leaders, he told the summit.

An agreement to cease hostilities first reached in January 2014 in Addis Ababa has failed to prevent bouts of fighting between government forces and rebels, largely concentrated in oil-rich regions. Repeated violations of the truce this month caused further “distress” among mediators, said Seyoum.

‘Political Ambitions’

Discussions over five days between Kiir and Machar on distributing power in the transitional government ended deadlocked on Feb. 1. Machar’s movement is pushing for the same proportion of posts as Kiir loyalists during this round of talks, his spokeswoman, Ann Norman from Norman Communications, said in an e-mailed statement late Sunday.

The war is ongoing because of “political ambitions and egos,” said John Luk Jok, the leader of a faction of South Sudanese leaders who aren’t directly involved in the fighting.

“This war can only be considered by the people as a cruel game of the political elites who are oblivious to the suffering of their people and interested only in power for themselves,” he said at the ceremony.