A gunman shot dead five people at defence contractor Lockheed Martin's plant in Mississippi before killing himself. Eight people were wounded and taken to hospital.
"He went through the entire plant, shooting individuals. He had a shotgun and a semiautomatic rifle and he appeared to open fire at random on employees," Lauderdale County Sheriff Billy Sollie said.
He said the gunman was a Lockheed Martin employee.
The Meridian plant builds parts for the C–130J Hercules and vertical stabilizers for F–22 Raptor jets, which are assembled at the plant in Marietta, Georgia, along with military transport planes.
Lockheed Martin is the largest defence contractor in the United States and employs about 125,000 people.