It was the latest in a string of chillingly similar workplace massacres that has plagued the United States in recent years.

A police spokesman told AFP the gunman, whose identity was not released, arrived at the Lockheed Martin plant dressed in camouflage gear and armed with a revolver and semi-automatic rifle and opened fire at about 9:30 am.

Lauderdale County Sheriff Billy Sollie told CNN television the killings appeared to have been random, adding that "several of the victims were found at their workstations."

John Smith, the town's mayor, said Meridian was traumatized by the attack.

"There's shock, there's horror and great, great grief," he told CNN. "It's not supposed to happen in a city like Meridian.

"Who knows what goes through the human mind, the human heart?"

Meridian, population about 30,000 people, is near the border with Alabama. Its economy is heavily dependent on military contracts.

Lockheed Martin, whose plant here is about 20 years old, said in a statement from its Marietta, Georgia, office that it was "shocked and saddened by this tragedy and express our deepest sympathies to the families" of the victims.

The company, headquartered in Bethesda, Maryland, next to Washington, is a key US defense contractor whose products include components of the F-16, F/A-22, F-35 JSF, F-117, T-50, C-5, C-130, C-130J, P-3, S-3 and U-2.

Tuesday's shooting was the last in a string of workplace massacres in the United States in recent years.

The last was in Jefferson City, Missouri, last Wednesday, when an employee in an auto parts factory killed four co-workers, wounded five, then killed himself.

On September 10, 2001, Joseph Ferguson, 20, just fired from a Sacramento, California, security firm, killed four people at the company, including his former girlfriend, and fled, killing a fifth person before taking his own life.

On February 5, 2001, Willie Baker, 66, who worked 40 years for a Chicago area motorworks before being fired for theft six years earlier, returned to the factory and killed four former co-workers, then himself.

On December 26, 2000, 42-year-old Michael McDermott killed seven of his colleagues in a Boston-area computer firm after learning the Internal Revenue Service was about to garnish part of his salary for tax arrears.

On November 2, 1999, Bryan Uyesugi, 40, a 15-year Xerox technician in Honolulu, Hawaii, shot dead seven colleagues at work. His explanation to police: he was "unhappy."

On September 14, 1999, in Anaheim, California, 42-year-old Dung Trihn, apparently distraught over the death of his mother in a hospital, opened fire in the hospital, killing three.

On August 5, 1999 a 34-year-old man facing dismissal killed his boss and two colleagues in Pelham, Alabama.

And on July 29 1999, Mark Barton, a 44-year-old stock speculator, killed five people in two brokerage firms before taking his own life. He told police, he had come "to hate this life, in this system."

Two days earlier, Barton had killed his wife and two children.

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