War-hit Sudan is sliding into a "widening famine crisis" that has been marked by worsening starvation and a surge in acute malnutrition, an independent group of food security experts says.

Famine has spread to five areas, with 24.6 million people - about half the population - in urgent need of food aid, the experts said.

The hunger crisis has been caused by the 20-month civil war that has devastated Sudan.

Various mediation efforts aimed at ending the conflict between the army and the paramilitary Rapid Support Forces (RSF) have so far failed.

The army and RSF had jointly staged a coup in 2021, but a power struggle between their commanders plunged the country into a civil war in 2023.

It has led to one of the world's worst humanitarian crises, with the UN-backed Famine Review Committee (FRC) warning that a "greater catastrophe" could unfold if the conflict did not end.

The committee is linked to the Integrated Food Phase Classification (IPC) - a global initiative by UN agencies, aid groups and governments to identify famine conditions.

On Monday, Sudan's military-backed government announced it was suspending its cooperation with the group, accusing it of issuing "unreliable reports that undermine Sudan's sovereignty and dignity", Reuters news agency reports.

The IPC had first identified a famine in August at the Zamzam camp in Sudan's Darfur region, where about half a million people were taking refuge.

In its latest report, the FRC said that famine had now also hit the Abu Shouk and al-Salam camps in Darfur's besieged city of el-Fasher, as well as two areas in South Kordofan state.

"Famine is the most extreme manifestation of human suffering, representing a catastrophic collapse of the systems and resources essential for survival," the FRC said.

"It is not merely a lack of food but a profound breakdown of health, livelihoods and social structures, leaving entire communities in a state of desperation," it added.

The FRC predicted that five further areas in Darfur could face famine by May, and there was a risk of it spreading to 17 other areas.

"In areas of high conflict intensity, the hostilities severely disrupted farming activities, resulting in farmers abandoning their crops, looting and stock destruction," it added.

Both Darfur and South Kordofan have been hit by some of the worst violence, with scores of civilians killed, raped and abducted by gunmen.

In May, US special envoy for Sudan Tom Perriello said that some estimates suggested up to 150,000 people had been killed in the conflict across the country.