Abd Alkader Habak was busy doing his job, taking photographs, when the explosion happened.

The Syrian opposition photographer and activist was briefly knocked out by the blast, in the outskirts of Aleppo, but quickly got up to find carnage around him.

He decided not to take any more pictures, putting down his camera to help the wounded instead.

The first child he found lying on the floor was dead. The second was alive but barely breathing.

He picked him up and began to run towards safety.

The picture of Mr Habak clutching the boy, aged around seven years old, has been shared on social media tens of thousands times since they were published after Saturday’s attack. The particular photograph cutting through the many images of war coming out of Syria.

"This child was firmly holding my hand and looking at me," Mr Habak, 24, told CNN.

"The scene was horrible -- especially seeing children wailing and dying in front of you," he said. "So I decided along with my colleagues that we'd put our cameras aside and start rescuing injured people."