Shocking footage has emerged showing a Paraguayan police officer violently attacking a handcuffed 13-year-old boy.

The policeman is seen punching and kicking the boy in the corner of a squalid police cell.

First the officer punches him in the stomach and head.

Then he puts a bucket on his head to and proceeds to kick him several times around the body.

The boy, who had been picked up on a petty theft charge, appears to be in agony and shock after the assault.

Paraguay's interior minister Rafael Filizzola said the incident was being investigated.

"We want that the investigation is not limited to this person that has been identified here," he said.

"The responsibility of his superiors will also be evaluated."

Authorities are due to take a statement from the officer involved in the leaked police camera footage.