Large parts of South Sudan risk famine early next year as the world's youngest nation struggles to overcome a war that has left millions homeless, Save the Children said on Wednesday.
"If the current conditions continue, a famine is likely in 2018," said Bester Mulauzi, the charity's director of programmes in South Sudan.
"The situation is quite dire," he told the Thomson Reuters Foundation in a phone interview from South Sudan's capital.
"Malnutrition among children under five is alarming."
Absent new action, Mulauzi said famine was likely to hit in February or March and affect half to two-thirds of the country.
Earlier this month, food security experts said more than 1.1 million children under five would be malnourished in 2018, with nearly 300,000 "at a heightened risk of death".
They also estimated that 5.1 million people, or nearly half of the population, would continue to face food insecurity, with the "lean season" - when households run short of food before the next harvest - starting three months earlier than usual.
South Sudan descended into civil war in 2013 after President Salva Kiir fired his deputy, unleashing a conflict that has spawned armed factions that often follow ethnic lines.
At a press conference in Juba, Alain Noudehou, the humanitarian co-ordinator for the United Nations (U.N.), stressed the need for food and for free and consistent access to those people requiring outside help.
"The number of people in need of food assistance is expected to grow in 2018. This will continue to be a major challenge for the country and the for all humanitarian actors," he said.
South Sudan has ordered that humanitarian aid convoys be allowed to move freely around the country, two weeks after the United States said it had lost trust in Kiir's government and threatened to pull support.
Aid agencies, however, said they were able to reach people in dire need, with some 4 million rendered homeless by the war.
Hajir Maalim, a regional director for Action Against Hunger, told the Thomson Reuters Foundation that the agency has set up mobile teams that are agile and can quickly respond to needs.
The biggest worry, Maalim said, is funding, as humanitarian crisis in many parts of the world vie for donor attention.
Of the $1.6 billion needed for humanitarian needs in South Sudan in 2017, only 69 percent has been funded.
"We know the needs are there, we know how to address them," Maalim said. "But do we have the resources to be able to do that? That has been the concern."