A heartbroken Syrian father has told of how he innocently sent his wife and children to their deaths during the chemical attack in Syria.

Abdelhamid al-Youssef, 29, instructed his wife to take their twin babies into a basement when missiles began striking Khan Sheikhoun on Tuesday 4 April. After all, that was the safest place to hide during a bombing.

Little did al-Youssef know that the planes were dropping nerve gas – lethal chemicals heavier than air that would sink into the bottom of the building and kill his family.

"Hours later rescuers found them in a basement near our house, dead, with foam in the noses and mouths," Youssef told The Times. "When I saw them, I did not expect that. Oh God!"

Al-Youssef's wife and 9-month-old twins were just three of the 22 family members he is reported to have lost in the chemical weapons attack on Khan Sheikhoun, which was allegedly carried out by the Syrian regime.

The Times reported that 86 people were killed in the atrocity, 30 of them children, while a further 540 were injured. Turkish investigators confirmed yesterday (11 April) that Sarin gas had been used in the attack.

Many of the wounded were taken to the al-Rahma hospital, which was later bombed by fighter jets, raising suspicions that an attempt had been made to destroy any evidence of chemical agents.

Al-Youssef said he first woke at 6.45am when a missile struck the town. When he saw another crash into buildings near his parent home he decided to go and help them, leaving his wife with the well-intentioned instructions that would ultimately kill her and their children.

The fate of the rest of his family was equally abysmal. He first noticed a strange smell when he reached the family home. Then he saw the bodies.

"The first person I saw was my brother Yasser," he said. "He had clearly tried to rescue my other brother, Ammar, but he couldn't. They died on top of each other."

Khan Sheikhoun victim
Medics treat a Khan Sheikhoun attack victim Gettyy

The nightmare continued as he moved upstairs.

"I found Yasser's wife and their son Mohamed dead on the ground. I tried to hurry, as the gas had started to affect me, he said.

In the next room he came upon his young niece, praying that she was not also lifeless.

"I had tried to pick her up, even though I knew in my heart she was dead. But then the gas overcame me, I felt dizzy. I could barely breathe or see."

Al-Youssef succumbed to the sarin himself and was carried to hospital. When he came round he asked people about the fate of his wife and children. Rescuers broke the news to him then brought him the bodies.

He cried and sobbed and wailed.