A network of community kitchens in Sudan - a crucial lifeline for millions of people caught up in the civil war - is on the verge of collapse, a report says.

The warning from aid organisation Islamic Relief comes after a UN-backed global hunger monitor confirmed that famine conditions were spreading in conflict zones.

The locally run kitchens have operated in areas that are difficult for international humanitarian groups to access, but are facing closure due to neglect, shortages and volunteer exhaustion.

Sudan's people have been brutalised by more than two years of war after fighting broke out between the army and the paramilitary Rapid Support Forces (RSF).

It has created what the UN has called the world's largest humanitarian crisis, with estimates that more than 24 million people are facing acute food shortages.

Most of the kitchens "will close if nothing changes in six months, with maybe one or two surviving in each area", one volunteer is quoted by the Islamic Relief report as saying.

These local initiatives often operate alongside social networks known as Emergency Response Rooms that have filled the gaps of collapsing government services and limited international aid.

Everyone from teachers to engineers to young people pitch in.

Financial fragility is the most pressing issue the kitchens face. They are now funded mainly by the Sudanese diaspora, after the USAID cuts earlier this year.

"It was like someone cut a rope we were holding on to," one volunteer said.

"Before March, we had a small, regular stream that let us plan. We knew we could serve at least one meal a day. Now? In the last month, I would say there were 10 days we went to sleep not knowing if we could cook the next day. The uncertainty, it's worse than having nothing."

There are severe operational challenges, such as the lack of safe water and firewood.

Aid agencies say both sides obstruct deliveries with bureaucratic delays and denials. To make matters worse, there are often market disruptions due to blockades, insecurity and looting.

The situation is worst in the besieged cities of el-Fasher in the western Darfur region and Kadugli in South Kordofan state. Both are largely cut off from commercial supplies and humanitarian assistance.

The latest report of the global food security monitor, the Integrated Food Security Phase network (IPC), confirmed famine conditions in those cities and projected a risk of famine in 20 additional areas across greater Darfur and greater Kordofan.

In el-Fasher, the kitchens were reduced to serving animal fodder by the time the city finally fell to the RSF last week.

Food security in Sudan shows stark contrasts along conflict lines, the IPC report says.

"Conflict still decides who eats and who does not."

In areas where violence has subsided the situation has begun to improve, it says.

And some international aid agencies are contributing to the Emergency Response Rooms, although they have not been able to replace the US funding.

But even in Omdurman, across the Nile from the capital, Khartoum, and largely under army control with ample commercial supplies, the scale of need often exceeds available resources, leading kitchens to ration food.

The city has been a hub for people displaced by the war, and prices are high.

"This is the hardest part of my day," a volunteer from Omdurman is quoted as saying.

"We don't have a formal system. We feed everyone, but one time we had to tell a mother at the end of the day that we had nothing left for her two children and that she should come back tomorrow early. She didn't even cry, she just looked deflated.

"I went home and I couldn't even speak to my own family that night. The shame of having food in my stomach when that child did not, it is a heavy feeling for me."

The Emergency Response Rooms have been hailed as a model for UN-led reforms that emphasise shifting power and resources closer to the people most affected by crises.

This year they were nominated for a Nobel Prize.

But after nearly three years, the volunteers find themselves increasingly on their own, facing burnout and danger.

They have to work with whoever is in control in their area, and have become targets when territory changes hands, because they are sometimes seen by both sides as collaborating with the other party.

Limited communications are a real problem. Long-term internet blackouts make it difficult to get money transferred through a mobile bank system, and mobile phones are a prime target for looters.

"They depend on this mobile money," Shihab Mohamed Ali from Islamic Relief Sudan based in Port Sudan told the BBC's Newsday programme.

"They are taking the money inside their mobiles and going to bring the commodities from far areas. So, they used to cross through different checkpoints. And sometimes they were being looted, their mobile taken. And if the mobile is taken, that means the money is taken."

Worse, he says, "there are some reports of members of community kitchens who were even killed".

"My biggest fear is that in six months, the community will be completely exhausted," says a volunteer from Khartoum.

"We are all getting poorer and angrier."