Al-Samah, near Mosul - Four men clung to the black Humvee as it careered toward the east Mosul field hospital. Anguish marked their faces, blood stained their clothes and they cradled between them the broken frames of two slightly built boys - victims of a mortar strike minutes earlier.

A crowd rushed forward to meet the vehicle, helping to lift the casualties on to stretchers under a shroud of settling dust. Matham, 15, was unresponsive - head back, mouth open, gaze unfocused - and an ugly red stain had soaked through his clothes at the neck. A medic placed him on a stretcher, examined his wounds and put two fingers on his carotid artery, searching for a pulse.

The 12-year-old Mohammed lay on a nearby cot. He was conscious, but his right leg was torn open from ankle to groin and dangled sickeningly. A crowd of doctors cut away his trousers then applied a tourniquet to halt the massive blood loss.

He called weakly for his mother as they worked then closed his eyes. "Is he breathing?" someone asked urgently. "Is. He. Breathing?" A few seconds later, the boy groaned, asked for water, then lay with his head tilted sideways staring at the sky.

Mohammed, 12, and a 15-year-old neighbour are carried from an Iraqi army Humvee at an outdoor field clinic in Mosul's Samah district. The boys were hit in a mortar attack that shredded Mohammed's leg and killed Shafiq [John Beck/Al Jazeera]

A middle-aged woman in a white headscarf and black polka dot dress skirted the clinic wall and rushed frantically forward, calling the younger boy's name. Male relatives intercepted her a few metres from the cot, took an arm each and coaxed her away.

She turned her head as she walked, looking back at a scene that has become increasingly common as civilian casualties of the month-long offensive to retake Mosul from the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) continue to mount.

The military-run field hospital is the forwardmost facility along this front. It's set up outside a battle-scarred house in the city's al-Samah district: 10 dark green cots folded out on the irregular ground of a compound still littered with spent bullet casings. It smells of dust, cigarettes and smoke from burning piles of used bandages and gauze. Supplies are piled on the back of pickups.

A team of more than 20 Iraqi and foreign volunteer medics take shifts treating as many as 50 casualties every day. The priority is to stop bleeding and stabilise patients to the point that they can be sent on to better-equipped facilities in IDP camps, army bases or the nearby city of Erbil.

This is more difficult than Ramadi and those areas. ISIL know it is their last land so they are trying their best to kill as many as possible.

Captain Ala, Clinic worker

Gogjali was only recently cleared of ISIL fighters and a large military presence remains in the area. But there are civilians too. Some preferred to stay in their homes regardless of the fighting and now sit on doorsteps cautiously chatting and smoking.

Many more arrive every day from further into Mosul, trudging along roads or barren hillsides holding white flags and battered suitcases, then converging on an Iraqi army gathering point opposite the clinic. There they are ushered on to trucks and taken to recently constructed camps on the Erbil road.

There had been a run of military and civilian casualties that day, but the afternoon brought respite. The medics relaxed in the last of the sun, lounging on plastic chairs or with their backs to a breeze block wall.

Regular outgoing artillery fire from a nearby battery punctuated the murmur of conversation, as it had done for hours. No one appeared to notice. Then came the crash of a mortar landing nearby and another quickly afterwards. The hospital crew looked up as black smoke rose a few hundred metres beyond the compound wall.

The shells had torn into Matham and Mohammed as the two, who had been neighbours, made their way towards the IDP assembly point with their families.

A nearby squad from the elite Counter Terrorism Service (CTS) hauled the boys on to their Humvee hood, one of the soldiers helping three family members to hold them as it sped the short distance to the clinic.

It was quickly apparent that Matham had died from his wounds by the time they arrived. A burly, goateed medic gently closed the boy's eyelids and covered his face with a blood-soaked jumper. Two black uniformed CTS soldiers then unfolded a light grey body bag on the ground next to the stretcher. Matham had been small for his age and it only took one to move him.

The father of Maytham, 15, opens the body bag containing his son at an outdoor clinic in Mosul's Samah district. Maytham was killed by a mortar attack minutes earlier [John Beck/Al Jazeera]

His father rushed over as they begin to zip up the bag, dropped to his knees and kissed his son's cheek again and again, collapsing on top of him. A doctor carefully pulled him back, while the soldier and a relative placed the body on the ground next to an ambulance. His silver-haired grandfather and two other relatives crouched there among empty water bottles and discarded food containers, sobbing.

A small boy from the house next door to the clinic sat on top of the wall and watched, expressionless.

Meanwhile, Mohammed had been stabilised and what was left of his leg bandaged up. Medics moved him to an orange-framed stretcher and into a waiting ambulance that bounced off along the irregular road. No one seemed sure whether he'd live, and even if he did, his leg would likely have to be amputated, an American volunteer who'd treated him said.

Having done all that they could, the clinic staff relaxed again, even posing for a smiling picture with a news crew security guard who'd arrived with a leg wound shortly after the boys.

A few metres away, Matham's grandfather opened the bag a few inches to say a final goodbye. The sturdily built patriarch stared for a moment then cried and cried, eventually collapsing back cross-legged, where he remained, crippled by grief, with one hand over his face.

These kinds of injuries are distressingly typical, said clinic head Colonel Khalil Jawad Kadim. "We see gunshot wounds, head wounds, amputations and shrapnel in all parts of body," he explained, perched on a lawn chair during a quiet moment. Kadim, a small man with a soft handshake and hint of grey moustache, added that recent days had been some of the worst he's seen in his 26-year medical career.

A colleague, Captain Ala, who worked in similar field hospitals during previous battles against ISIL, added that ISIL fighters were desperately defending the only major Iraqi urban centre still under their control.

"This is more difficult than Ramadi and those areas," he said, referring to offensives in Anbar province. "[ISIL] know it is their last land, so they are trying their best to kill as many as possible."

Mosul: A look inside ISIL’s extensive tunnel system

Commanders reported there were no major operations taking place that day, but fighting further into Mosul was still heavy. Around noon a radio crackled with the news of an ISIL suicide car bomb attack. A Humvee roared up soon afterwards with a casualty lying across the back seat.

A medic examined him as others rushed to prepare a stretcher. "No," he yelled, urgency suddenly evaporated. "We need a body bag."

Sergeant Ali Jafar arrived later with bullet fragments in his arm from clashes in Mosul's al-Zahra, formerly known as Saddam district. He chatted to medics as they probed and washed out his wound using iodine solution from a water bottle, grimacing only when they tightened his bandage, then quickly breaking into a smile.

ISIL have been fighting hard, Jafar said. Their typical tactics involve teams four or five strong employing sniper rifles, rocket-propelled grenades and mortars from inside densely populated areas, sometimes even using the roofs of inhabited homes as firing positions.

Worse still were the suicide car bombs, he said, describing an incident the previous day when his squad had been forced to use their own Humvee as a barrier to stop one advancing.

His commander, Captain Sarmad al-Saadi, derided ISIL's methods as cowardly. "They only use suicide attacks," he said lighting up a slim cigarette.

READ MORE: Iraq - 'Now we have a grave to visit'

Iraqi commanders stress that they are doing everything possible to avoid civilian casualties, but Ala, the medic, says that a growing proportion of the patients they treat are non-combatants.

The danger is not only of stray bullets or bombs. Both soldiers and civilians describe ISIL targeting residents attempting to flee. "They are doing that every day," Saadi says. "They want everyone to stay as a human shield."

Recent victims included three-year-old Jawahar, a tiny, curly-haired girl in a red top who'd been hit in the foot with bullet fragments. Her uncle, Ahmed, said that they'd joined a large group attempting to move towards the relative safety of the Iraqi army in al-Zahra when ISIL fired on them from the other end of the street, hitting several people.

"[ISIL] are shooting people who try to leave," he said. "They think we are unbelievers going to the land of unbelievers."

Iraqi troops are still fighting on Mosul's outer edges, but as they push deeper into the city against determined and ruthless resistance, hundreds of thousands more civilians are expected to be displaced.

With few ways out that don't involve a gauntlet of violence, medics at the frontlines expect many more Mohammeds and Mathams to come.

Source: Al Jazeera