Eight members of one family, including a teenager, were shot dead in rural Ohio on Friday, just before gunmen killed six people in Georgia.
Ohio police yesterday hunted for one or more gunmen who massacred eight members of a family in execution-style killings, but appeared to spare two babies and a toddler.
Seven bodies, each with a bullet to the head, were found at three houses in the village of Peebles - a rural community 130km east of Cincinnati - and an eighth later at a separate site, police said.
The victims - several of whom were asleep in bed when they were killed - were “all adults except for a male juvenile” who was 16, Ohio Attorney General Mike DeWine said.
All were members of a single family.
A baby aged just four days and another of six months, and a three-year-old child, survived the shootings. Authorities gave no possible motive and no arrests have been made.
At least one suspected gunman was on the loose, a day after the shootings, and police warned residents to lock their doors as they undertook a massive search.
“There is a threat there and I believe that threat to be armed and dangerous,” Pike County Sheriff Charles Reader said.
Investigators have interviewed more than 30 people in connection with Friday’s killings.
“We do not know if we are talking about one individual or two or three or more,” DeWine said.  “Each one of the victims appears to have been executed, each one of the victims appears to have been shot in the head.”
A woman whose newborn baby lay next to her was among the dead.
“It’s just a terrible thing,” Sally McDaniel, a family friend, told ABC News. “You’d have to be a monster to go in and do something like that.”
Schools in Pike County and surrounding areas were placed on lockdown as a precautionary measure, local media reported.
Ohio Governor and Republican presidential candidate John Kasich tweeted that the killings were “beyond comprehension.”
Separately, six people were found dead in northern Georgia, in two separate incidents believed to be a domestic dispute, Columbia county sheriff’s officials said, according to television reports.
Local coroner Vernon Collins said five people were dead in two shootings that are possibly connected, the report added.
Firearms kill around 30,000 people in the US each year.
However, Republican lawmakers, some of whom are backed by the powerful National Rifle Association, have blocked President Barack Obama’s attempts to pass gun control legislation.