Unknown gunmen have executed seven family members, including three children, in their rural South African home, police said on Thursday.

Among the victims was a five-year-old boy who were shoot at their home in the eastern KwaZulu-Natal province late Wednesday.

The eldest victim was a 55-year-old woman.

Police is yet to establish the motive behind the attack in the highlands area, about 80 kilometers (50 miles) Northwest of the coastal city of Durban.

"We are convinced as police that it was an execution. It was a planned murder," provincial police commissioner Nhlanhla Mkhwanazi told reporters outside the house.

Some of the victims appeared to have been shot in the head while on the floor, he said.

"There was a total of about 25 bullets that were used."

The gunmen burst into the house as the family was watching television and made one member of the family, who was outside the house, knocked on the door and then opened fire once it was opened.

South Africa has one of the highest peacetime per capita homicide rates in the world.

Nearly 6,200 people were murdered in the country between April and June, according to police figures released in August.