HONG KONG: A doctor leapt into a river in central China to save a six-week-old baby girl who had been thrown into the water in an apparently random attack by a total stranger.

The incident happened on Friday as a woman identified only as Liu was pushing her infant daughter in a pram across a bridge in Pingdingshan, Henan province, the Legal Evening News reported on Sunday.

Standing on the bridge was a 28-year-old man with the surname Qin. As Liu passed, Qin reached down into the pram, picked up the tiny child and without saying a word threw her into the water more than six metres below, the report said.

The horrified mother screamed for help and was heard by an off-duty surgeon from a local hospital and a second man who were walking beside the river.

The two men ran into the water and carried the 43-day-old baby back to dry land. Realising she was not breathing, the doctor, identified as Ge Haifu, slapped the tiny child on her back and performed cardiopulmonary resuscitation on her.

He also stripped off her soaking clothes and wrapped her in a blanket to keep her warm until an ambulance arrived and took her to hospital.

The report said the baby was in intensive care but in a stable condition.

Police detained the suspect the following day in neighbouring Jiaxian county and said a formal investigation was under way.

Liu said she had never seen the man before. — SCMP