Fears of genocide and famine in war-torn South Sudan dominated the agenda Thursday of US Secretary of State John Kerry, as he launched an Africa tour focusing on the continent's most brutal conflicts.
Kerry arrived late Wednesday in the Ethiopian capital on his first major tour of Africa, which will also include Democratic Republic of Congo and Angola.
Ethiopia has been hosting peace talks between South Sudan's government and rebels aimed at ending a bloody four-month civil war.
But there is mounting outrage at the scale of killings, with both government forces loyal to President Salva Kiir and rebels backing ex-vice president Riek Machar implicated in massacres, rapes, attacks on UN bases and recruiting child soldiers.
Thousands of people have already been killed -- and possibly tens of thousands -- with at least 1.2 million people forced to flee their homes in the country, the world's youngest, which won independence from Sudan only in 2011.
Addis Ababa is the headquarters of the African Union, and in meetings Thursday Kerry is expected to discuss conflicts not only in South Sudan, but also in Central African Republic (CAR), Somalia and DR Congo.
South Sudan peace talks resumed again on Monday after long delays but have made little progress.
A ceasefire signed in January is in tatters, with tens of thousands of people sheltering in UN bases following a wave of ethnic massacres and other war crimes.
Kerry will "push for both sides to honour the agreement that they signed", a US diplomat travelling with the delegation said.
The United States was instrumental in helping South Sudan gain independence, and Kerry is expected to try to press the negotiators at dragging peace talks.
"Both sides think that they can win this militarily, and they have certainly not participated in any committed way to finding a negotiated settlement for the conflict," the diplomat added.
The war has taken on a bitter ethnic dimension, pitching the Dinka people of Kiir against the Nuer of Machar, but the diplomat said the heart of the conflict was rather a personal "Riek Machar-Salva Kiir battle".
Washington is expected to deliver a "tough messages" to the warring parties, warning they will be held accountable if "they don't take the necessary actions to end the hostilities", the diplomat added.
Sanctions have been threatened although Kerry is not expected to announce specific names, the diplomat said, although the US is drawing up a list of individuals.
But time is short to end the crisis.
Kerry landed in Ethiopia hours after top United Nations rights officials vowed they would to do everything in their power to prevent the country from sliding into genocide, and warned of the growing risk of famine.
Firing off a damning attack against both Kiir and rebel leader Machar, the UN's High Commissioner for Human Rights Navi Pillay said she was "appalled by the apparent lack of concern about the risk of famine displayed by both leaders."
"The deadly mix of recrimination, hate speech, and revenge killings that has developed relentlessly over the past four and a half months seems to be reaching boiling point," Pillay said Wednesday.
The UN this week made a desperate appeal for a one-month truce to avert a famine and humanitarian disaster.
"To the survivors of the genocide, we owe a pledge to take all possible measures within our power to protect populations from another Rwanda, there is no excuse for inaction," said UN envoy for the prevention of genocide Adama Dieng, who travelled with Pillay.
"It is clear that the conflict has taken a dangerous trajectory, and civilians are being deliberately targeted based on their ethnicity and perceived political affiliation," he added.