Eight family members have died following shootings in the US state of Ohio yesterday.

Pike County Sheriff, Charles Reader, said they appeared to be 'execution-style' killings and that no arrests had been made.

Seven adults and a juvenile are said to be among those killed.

Three children are reported to have survived the killings.

More than a dozen officials from multiple agencies were sent to crime scenes in Piketon, an Appalachian region 120km east of Cincinnati.

In a statement, local authorities said they were "still investigating to determine a motive, identify the deceased, and determine if the gunman is among the deceased individuals or on the loose".

Earlier, local schools Peebles Elementary and Peebles High School were on "lockout", with people prevented from entering or leaving, due to the ongoing situation in Piketon, a spokesperson for Adams County Ohio Valley Schools said.

The FBI in Cincinnati have tweeted that they are "closely monitoring the situation in Pike County".

Ohio Governor John Kasich, a Republican presidential candidate, tweeted that the situation is "tragic beyond comprehension".