A grieving father sobbed as he carried his infant twins, wrapped in matching white shrouds, to their graves.
Ahmad and Aya, nine months old, died on Tuesday morning in a chemical attack on the town of Khan Sheikhoun in Idlib, northern Syria, along with their mother Dalal and 16 other members of their family.
On Wednesday Abdulhamid al-Youssef had to bury them all in an unmarked mass grave.
The 29-year-old shopkeeper told reporters that he had been at work when the air strike hit close to his home just after 6.30am.
His wife called to tell him what had happened so he rushed home to be with them.
The children appeared to be fine, but as a precaution he took them all down to the basement of a nearby building in case of another strike.
It was only then, an hour later, that they began displaying symptoms.
“The family was all waiting down there and were safe, but then they started choking,” Mr Youssef’s cousin, Alaa, told the Telegraph. “The twins suddenly began shaking and struggling to breathe. Then he watched the chemicals take hold of his wife, then his brother, nieces and nephews.
“Everyone died down there in the basement, they didn’t have time to get to the hospital,” he said. “All Abdulhadim kept saying to me after was ‘I couldn’t save any of them, brother, I couldn’t save them’.”
Mr Youssef hugged his children – who looked peaceful in death – one last time before laying them into the ground. Apart from a bruise on Ahmad’s cheek there were no obvious signs of injuries.
“Chemical attacks leave no marks,” said Dr Mamoun Najem, a doctor at al-Rahma hospital in Idlib who treated the victims. “It’s a silent killer that works its way through the body slowly.”
The attack happened around 6.32am local time. A video distributed by opposition activists claiming to be of the moments after the air strike, which hit Corniche Street in a northern neighbourhood of Khan Sheikhoun, showed several large plumes of smoke.
“The sound of the explosion was not what we are used to – I thought that this one hadn’t exploded, because of the thump sound it made, not an explosion sound,” one witness said.
Alaa al-Youssef said he heard planes circling above before they dropped their load 300ft away. The wind had been blowing west and away from Mr Youssef’s house, but had it not been he believes he would almost certainly be dead.