Sayyid Abdul Azim, Associated Press
US Secretary of State John Kerry speaks, during a joint press conference in Nairobi, Kenya, Monday, Aug.22, 2016. Kerry says much has been achieved toward bringing peace in Somalia but much more needs to be done to stop the extremists waging an insurgency against the western backed government.

NAIROBI, Kenya — East African foreign ministers from countries including South Sudan have agreed to move ahead with the deployment of a regional peacekeeping force to that troubled nation, U.S. Secretary of State John Kerry said Monday on the first stop of his latest Africa visit.

South Sudan at first rejected the regional protection force after the U.N. Security Council earlier this month voted to deploy the 4,000 additional peacekeepers to help restore calm. Fighting that erupted in the capital last month killed hundreds amid widespread reports of rapes and other abuses and raised fears of a renewed civil war.

There is "absolutely no question" that the force should be deployed, Kerry said after the meeting with foreign ministers. He did not say when the force might be sent into South Sudan.

A spokesman for South Sudan's president, Ateny Wek Ateny, again expressed the belief Monday that the regional protection force violates South Sudan's sovereignty, but he said the country's transitional legislature could decide this week if they will accept its deployment. "The people should decide," he said.

Kerry said the force is "supplementary to the sovereignty and efforts of South Sudan itself, and I think we had a good clearing of the air in the discussions we had."

The secretary of state is in Kenya, East Africa's biggest economy, to discuss regional security and terrorism with regional leaders. He then will visit Nigeria for similar discussions.

Kerry also announced nearly $138 million in humanitarian assistance from the United States to South Sudan, where a humanitarian crisis has worsened amid the recent turmoil.

He added that the U.S., the largest donor in South Sudan, had made it clear that the help has a limit.

He said South Sudan's leaders have been asked to recommit in "word and deed" to the peace accord signed in August 2015 that was meant to end a two-year civil war that cost thousands of lives and displaced more than 2.5 million people. Representatives from South Sudan's government indicated their full willingness to that, Kerry said.

"The leaders of South Sudan have to live up to their responsibilities. They have to put the interests of their citizens first, and they have to refrain from violent and provocative acts," Kerry said.

But the peace deal appears to be unraveling after former rebel leader and vice president Riek Machar, who had been reunited with rival President Salva Kiir under the peace deal, fled amid last month's fighting. A spokesman announced last week that he had crossed into neighboring Congo. His current location is unknown.

On another regional crisis, war-torn Somalia, Kerry said extraordinary progress has been made in stabilizing the Horn of Africa country but much more needs to be done.

He said he and the East African foreign ministers agreed on the need to strengthen Somalia's institutions ahead of elections in September and October. They also agreed to ensure that African Union troops have the needed resources to partner with Somalia against extremists.

Somalia was plunged into chaos in 1991 following the ouster of longtime dictator Siad Barre by warlords who then turned on each other. The homegrown, al-Qaida-linked extremist group al-Shabab continues to launch deadly attacks.

Associated Press writer Justin Lynch in Juba, South Sudan, contributed.