Three people - including the aggressor - were dead after a shooting early Friday inside a New Jersey supermarket, U.S. media reported.

The incident took place at a Pathmark grocery store in Old Bridge, a town about 56 kilometers (35 miles) from New York.

The shooter, a 23-year-old Pathmark employee working the night shift, left the store around 3:30 a.m. only to return armed with a handgun and an AK-47 assault rifle, the Middlesex County prosecutor's office said.

"He entered the store firing his weapons," county prosecutor Bruce Kaplan told a press conference.

After killing two co-workers, the attacker killed himself.

Police evacuated the other Pathmark employees, Old Bridge Mayor Owen Henry told the Star-Ledger newspaper.

"This is the worst phone call a mayor can receive," he said of the 6:30 a.m. call informing him of the shooting. "You can prepare for these things but you can't prevent them."

The violence in New Jersey comes a week after Jeffrey Johnson, a laid-off designer, fatally shot his former boss and was then killed by police outside New York's Empire State Building.

Nine passers-by were wounded in that incident. EFE