This is the heroic moment a quick-thinking passer-by caught a kid who was dragged into the air on an escalator handrail before plunging to the ground.

The father was sitting and looking at his phone at the bottom of the escalator while his son stood next to the moving device in Almaty, Kazakhstan.

However, the child in a white cap then lost his footing and was dragged up to the top where he was left hanging dangerously on the outside.

While the father tries to run up the escalator in a vain bid to reach the child before they fall, another man more sensibly runs underneath the child and catches him as he falls.

The dad then runs down and takes the child from the man's hands. He briefly thanks the Good Samaritan saviour before leaving,