Exclusive: Kareem Shaheen reports from Khan Sheikhun, where he was the first reporter from western media to reach the site of this weeks devastating atrocity

Khan Sheikhun is a ghost town, its streets deserted and silent as though mourning the victims of the atrocity that occurred here two days earlier.

The only reminder of what happened is a small, blackened, crater near the north of township, where a rocket laced with a nerve agent fell, killing more than 70 people in one of the worst mass casualty chemical attacks in the six-year war in Syria.

All that remains of the attack on the town in rebel-held Idlib province is a faint stench that tingles the nostrils and a small green fragment from the rocket. The homes nearby are emptied of the living.

The victims symptoms are consistent with sarin, the nerve agent that was dropped on an opposition-held area near Damascus in 2013, killing more than 1,000 people. After that attack the regime supposedly gave up its chemical weapons arsenal.

Moscow, Bashar al-Assads principal backer in the war, said the Syrian government had bombed a rebel-run toxic gas manufacturing plant in Khan Sheikhun, and that the gas were then leaked out.

A label marks the site of the attack. Photo: Kareem Shaheen for the Guardian

The Guardian, the first western media organisation to visit the site of the attack, analyzed a warehouse and silos immediately next to where the missile had landed, and found nothing but an deserted space covered in dust and half-destroyed silos reek of leftover grain and animal manure.

Residents said the silos had been damaged in air raids six months ago, and had stood unused since then.

You can look at it; theres nothing there except maybe some grain and animal excrement, and theres even a dead goat there that suffocated in the two attacks, one person said. Residents responded in disbelief to the Russian allegation.

There was no evidence of any build being hit in recent days or weeks near where so many people were killed and wounded by a nerve agent. The homes across the street seemed undamaged from the outside. There was no contamination zone near any build. Instead, the contamination region radiated from a pit in a road.

The warehouse next to where the missile landed now an abandoned space covered in dust. Photo: Kareem Shaheen for the Guardian

The Guardian interviewed witness, first responders, victims relatives and the wounded in an effort to reconstruct the attack. They offered fresh details that shed light on an incident that has prompted worldwide condemnation and refocused attention on the brutality of the Syrian war.

It was like Judgment day, said Hamid Khutainy, a civil defense volunteer in Khan Sheikhun.

Witnesses said the air raids began shortly after 6.30 am on Tuesday, with four bombings around the town. Initially they thought it was just another airstrike, until the first responders who arrived at the scene began falling to the ground.

Khutainy said: They told us HQ, we are losing control. We had no notion what they were trying to say. Then they said, come save us, we are unable stroll. So the second and third squads went with simply face masks. We could smell it from 500 metres away.

People described a scene of utter horror at the attack site. The wounded were shaking and convulsing on the ground, foaming at the mouth, their lips blue, passing in and out of consciousness.

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I procured children lying on the ground, in their last breaths, their lips running blue, said Abu al-Baraa, who lives nearby and rushed to assist when the full extent of what had happened dawned on him.

Standing across the street from the crater left by the missile, he added: People on the rooftops and in the cellars. People on the ground in the street. Wherever you seemed there were dead human beings.

Idlib map

The suffocating both patients and those who had died were taken to the nearby civil defense centre and the adjacent clinic built into the side of a rocky mountainous outcrop to withstand potential airstrikes. The dead were laid in a nearby shed while emergency employees hosed down the injured with water, and administered atropine, a nerve agent antidote.

But while medical workers were trying to come to grips with the crisis, between eight and 10 airstrikes targeted the medical facility and civil defence centre. The shed collapsed on the dead, and the site was put out of service.

Maybe the pilots heard the myth that you could come back to life 48 hours after succumbing from sarin, so they decided to bomb them again just in case, said an official from the Ahrar al-Sham rebel group who was on the scene. Thank God there is a Day of judgment in the afterlife.

The Guardian visited the destroyed medical facility and civilian defense centre briefly. Local people said reconnaissance planes had been spotted in the sky earlier and believed the region might be targeted again later in the day.

The site was filled with rubble. Inside, hospital equipment, beds, surgical instruments and small boxes of medicine lay covered in dust or broken on the ground. There were no weapons in sight, and the rooms inside the cave were darkened with the electricity knocked out.

In a nearby graveyard, the tombs were still fresh from funerals the day before, the red soil still upturned. In one corner 18 new tombs were put up, the names barely etched with a rough chisel on the tombstones. They contained the bodies of 20 people, including two children who were buried with their mother. They were all from the same family.

Abdulhamid al-Yousef, one of the few survivors in the family, was receiving condolences at his home in Khan Sheikhun, a day after interring his wife and nine-month-old twins, Ahmed and Aya, fighting back tears.

Yousef had rushed to help the other victims of the attack. He came back instead to find that much of his family had died, including siblings, nephews and nieces. His spouse and children had rushed down to the bomb shelter in their basement, only for the toxic gas to seep into it, which killed them all.

That evening at the cemetery, he insisted on carrying his two newborns in his arms to inter them himself. Almost in a trance Yousef repeated the childrens names, choking as he did so. Aya and Ahmed, my spirits. Yasser and Ahmed, my brothers who had my back. Ammoura and Hammoudi, Shaimaa, so many others, he said.

Read more: www.theguardian.com