Ahmed Abdul Rahman can hear the thud of artillery from where he lies in a makeshift cluster of tents in the Sudanese city of el-Fasher.

The 13-year-old boy was injured in a recent shelling attack.

I feel pain in my head and my legs, he says weakly.

For 17 months the paramilitary Rapid Support Forces (RSF) have besieged el-Fasher, located in their ethnic heartland of Darfur, and now they're closing in on key military sites in the city.

The conflict in Sudan broke out in 2023 following a power struggle between the top commanders of the RSF and the Sudanese army. After losing control of the capital Khartoum, the paramilitaries have stepped up efforts to seize el-Fasher - the army's last stronghold in the western Darfur region.

Army-held territory has shrunk to a pocket around the airport. For the tens of thousands of civilians trapped inside the city, each day is a nightmare.

The siege and fighting make it very difficult to get reliable information, but the BBC has worked with freelance journalists inside el-Fasher to get an insight into life for those trapped there.

Warning: This story contains graphic details that some people may find distressing

Ahmed's whole body is full of shrapnel, says his mother Islam Abdullah. His condition is unstable. But with hospitals coming under fire and running out of supplies, medical care is scarce.

She lifts Ahmed's shirt to reveal his wounds, his bony back a reminder of the hunger stalking the city.

Nearby, Hamida Adam Ali is unable to move, her leg is badly injured. She lay on the road for five days after being hit by shell fire before she was carried to the camp for people displaced by the conflict.

I don't know if my husband is dead or alive, she says. My children have been crying for days because there is no food. Sometimes they find something to eat, and sometimes they go to bed without food. My leg is rotting - it smells foul now. I am just lying down. I have nothing.

The RSF have made significant advances in recent weeks. They've released footage showing their fighters in a location which the BBC has identified as the headquarters of the military's armored corps.

In the past few days, it has posted a video of soldiers said to be cheering the arrival of much-needed supplies, reported to be delivered by airdrops.

Seizing full control of the city would give them a strategic advantage in the civil war after setbacks earlier this year, easing their access to Libya and strengthening their control over the western border in an arc stretching from South Sudan to parts of Egypt.

The paramilitaries deny targeting non-Arab ethnic groups, such as the local Zaghawa community, despite evidence of war crimes presented by the UN and human rights groups. They are trying to send a different message - with new videos showing them greeting and helping those who flee.

Hundreds of thousands have fled el-Fasher over the past year. Those who make it to safety say people were attacked, robbed, and killed as they left.

Last month, more than 75 people were killed in a strike on a mosque during morning prayers, an attack blamed on the RSF, although it didn't publicly take responsibility. The UN warns of more atrocities if RSF fighters overrun the city.

As the siege continues, the plight of el-Fasher's children remains dire, highlighting an urgent need for intervention and humanitarian assistance in a city under siege.