A Vietnamese teenager has been arrested for allegedly helping his mum cut off his father's penis.

The 17-year-old reportedly tied up his dad after his mum accused him of cheating on her.

Police in the central province of Quang Tri said the mother and son tied up the man before using a knife to cut off his genitals.

A police spokesman said: "The eldest child of the man and his wife cut him up before cutting his genitals with a knife.

"Some neighbours heard his screams and took him to hospital."

The 53-year-old man was taken to hospital too late to reattach his penis.

His three younger children were also in the house at the time, but were unable to prevent his alleged attackers.