South Sudan's government has agreed to end hostilities which have already displaced more than 120,000 people in the new country.
Since South Sudan broke away from Sudan in 2011, it has been plagued by power struggles within the ruling party.
In a speech at the Inter Governmental Authority on Development (IGAD) summit in Kenya, Kenyan President Uhuru Kenyatta noted there is "a very small window of opportunity to secure peace," in South Sudan. Fighting between South Sudan President Salva Kiir and former Vice President Riek Machar has raised fears of civil war.
Machar is accused of planning a failed coup, which he denies, and remains a fugitive wanted by the military.
Kiir and Machar have not met to formally discuss peace talks between the South Sudanese government and rebel forces.
The U.N. estimates about $166 million is needed to save the lives of those caught in the violence.
Toby Lanzer, a humanitarian with the U.N., believes the death toll is now over 1,000 people. The U.N. is also investigating rumored mass killings.
"We have heard reports of extra-judicial killings, arbitrary detentions of civilians, ill-treatment, abuse and also mass graves," said Hilde Johnson, head of the U.N. mission in South Sudan. "Our human rights officers have been working around the clock, throughout this crisis, and they are investigating these reports and allegations."