The United Nations issued an urgent appeal Tuesday for 1.27 billion dollars for aid for South Sudan, hit by a seven-week-old conflict that has forced close to a million people from their homes.
"The priority is to save lives now, and ensure that we have food, medicine and other lifesaving supplies prepositioned in the field, in easy reach of aid agencies before the rains hit and the roads become impassable," said Toby Lanzer, the UN's top aid official in South Sudan.
Describing the impact of the fighting as "devastating", he said there were 3.2 million people suffering the humanitarian consequences, including 900,000 people who have been forced to abandon their homes and thousands more wounded.
"Livelihoods have been lost, and people's ability to move livestock to pasture, to fish or to hunt, has been severely compromised," he said.
"I ask the international donor community to stand with the people of South Sudan and the aid agencies working here to help them before the situation gets even worse," Lanzer added.
Fighting broke out in South Sudan on 15 December between troops loyal to President Salva Kiir and those allied to ousted vice-president Riek Machar, and quickly spread throughout the country.
Entire towns have been destroyed in the violence, with aid agencies and analysts estimating that close to 10,000 people have lost their lives in little more than a month.
The government and rebels signed a ceasefire agreement in neighbouring Ethiopia on 23 January, but sporadic fighting has continued to rage.
The work of aid agencies has been complicated by widespread looting of humanitarian supplies by both sides in the conflict.
On Monday Unicef said it was "extremely concerned" after government soldiers were pictured carrying bright-blue backpacks that were supposed to be destined for children but had been looted from a UN store.
Vehicles, food stockpiles and medicines have also been looted from organisations including the International Committee of the Red Cross (ICRC), Doctors Without Borders (MSF) and the World Food Programme (WFP).