The BBC's Safa AlAhmad is one of few journalists to have reached the besieged city of Taiz, at the heart of Yemen's civil war. She found a city destroyed by shelling - and a doctor struggling to save the life of a six-year-old girl.
At the al-Thawra hospital in the besieged city of Taiz, doctors gather outside the operating room to discuss which of their patients will be left to die. Without enough medicine and oxygen to treat all those injured in Yemen's pitiless civil war, hard decisions have to be made.
On the day I arrived, in mid-December, the choice was between a tiny six-year-old girl, Asma, and an old man with a gangrenous wound to the abdomen.
Asma had been hit by shrapnel as she queued to collect drinking water from a lorry. Nineteen other children were injured in the attack, and five were killed. The impact had broken away a shard of Asma's skull as big as the palm of my hand. Despite the severity of her injuries, the trauma surgeon began a desperate effort to save her.
The smell in the operating room was nauseating - a stench of blood and disinfectant, and of the white surgical plaster that the surgeon was shaping in his hands to patch the hole in Asma's head. He worked fast, racing to complete the operation before the oxygen ran out and increased the damage to the child's brain.
The mortar that shattered Asma's skull was almost certainly fired by Houthi rebels as part of an eight-month campaign to wrest Taiz, Yemen's second-largest city, from the control of forces loyal to the country's internationally-recognised government. To that end the Houthis have mounted a siege on Taiz, cutting off nearly all routes into the city and preventing even basic supplies from getting in by road.
The only way around the road blocks are mule tracks and smugglers' trails through the Sabr mountains. Everything - flour, rice, cooking gas, diesel, medicine - has to come over these trails to reach the starving and embattled people of Taiz.
I reached the city on a narrow dirt path that wound high into the hills, taking us around the front lines but not beyond the range of the Houthi snipers. The trail carries a steady flow of pack animals laden with food, weapons, oxygen and gas canisters, and we often had to make way for camels and donkeys that were herded along the path by children. Among them was a boy no older than four carrying a single piece of firewood, struggling beneath the weight but determined to keep pace with a group of older boys.
There were other women on the trail, most wearing the traditional clothing of the mountains - flowing dresses of yellow, orange, or pink worn over loose trousers - and many carrying bundles of firewood on their heads. I was the only one wearing the black abaya, a garment not designed for scrambling across rocks.
For a while I walked with two women who were returning to Taiz from their village. They had set out at dawn and had been walking for over 10 hours. At times they sang to keep their spirits up, or stopped to catch their breath and take in the views of the Sabr range. From far below came the thud and crackle of the fighting.
The trail is also used to transport the injured and the dead. The bodies of those killed are carried over the pass and down to their graves. The wounded, fighters and civilians alike, follow the same route to reach the few hospitals that remain open in Taiz.
Reaching the hospital brings no guarantee of safety. Al-Thawra contains the only functioning emergency trauma unit in the city, but it is regularly targeted by Houthi fighters. Two days before I arrived, a mortar shell had killed two doctors and injured many others.
Even for those who make it on to the operating table, supplies are desperately short. The lack of general anaesthetic means that some patients go under the knife while conscious. Others are not operated on at all, because the few precious canisters of oxygen must be reserved for those with the most serious injuries and with a realistic prospect of survival.
In some cases, the patients' own families bring oxygen canisters to the hospital. But that was a luxury beyond the reach of Asma, who had no-one to accompany her or hold her hand.
She survived the operation and lay on the bed alone, her thin shoulders protruding from the blanket, her hair gone, her eyes swollen and darkened with bruising. Her family, said Dr Ahmed Muqbal, had been displaced by the shelling and, like so many in Taiz, were now destitute and scattered, searching for somewhere safe to take their remaining children.
Asma's face was covered by a plastic mask attached to a ventilator, and her tiny chest was moving as the machine breathed into her. But it was pumping only air - there was no oxygen left to give her, and without it her brain was unlikely to recover.
"We worked hard to save her life, but it can all be gone to waste because of the lack of pure oxygen," said Muqbal.
He looked deeply tired. In the next bed lay the old man with shrapnel wounds and gangrene. He died two days later.
On 25 December, two weeks after my visit, the al-Thawra hospital closed its doors to new patients. It had simply run out of oxygen and medicine.
Asma, too, has since died of her injuries.
- Years of civil and sectarian strife reached a crisis when the Houthis, a Shia rebel group, took control of Yemen's capital, Sanaa, in September 2014
- Six months later, in March 2015, a coalition of Arab states led by Saudi Arabia began a military campaign to force the Houthis from power and reinstate President Abed Rabbo Mansour Hadi
- The ensuing chaos has enabled Salafist jihadi groups - including both al-Qaeda in the Arabian Peninsula and the local franchise of Islamic State - to carry out terrorist attacks
- The UN says almost 3,000 civilians have been killed and more than 5,000 have been injured in the fighting, while at least 2.2m children are suffering from or at risk of malnutrition
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