Liang Lee didn't hesitate when he saw a tiny child dangling from a window in an apartment block.

Breathtaking footage shows the young man scaling the side of the building with his bare hands as he desperately races to save the boy.

The unnamed toddler was wedged in a security window, trapped in a precarious position after his parents had gone out.

Had he moved his head to the left or the right he would have fallen, Liang is certain.

Liang, who lives in a neighbouring block on a housing estate in Liaocheng, a city in the east of China's Shandong Province, heard the boy's cries and came rushing to help.

"I got here and found the boy barely moving," Liang said. "His legs were shaking. I decided to climb up as I thought he was in danger.

"The security window left a trace on the boy's neck. If the boy [had] turned his head, he would [have fallen] from the gap of the bars."

Liang climbed up using the bars and grills fastened over the windows of the building. When he reached the boy, he managed to lift him with one hand as he hung on desperately with the other.

Other residents, meanwhile, had called firefighters and held a quilt below Liang and the boy to try to catch them if they fell.

Eventually, a locksmith arrived and opened the door of the boy's home and together they pulled him - and Liang - into the room. The boy's parents eventually arrived home later and are said to have thanked Liang profusely.