At least eight people have been killed in "execution-style" killings in four separate homes in rural Ohio.

It is believed the victims - seven adults and one teenager - are from the same family, the state's attorney general said in a statement.

They were all shot in the head and police are still searching for the attacker, or attackers.

More than a dozen officials from multiple agencies were sent to crime scenes in Piketon, south of Columbus.

A pastor at the scene said the violence may have been the result of a "domestic situation".

All of the victims are members of a family called Rhoden, said Pike County Sheriff Charles Reader.