LAST UPDATE | 11 Dec 2019

Emergency responders outside the kosher supermarket. Seth Wenig / AP/Press Association Images Seth Wenig / AP/Press Association Images / AP/Press Association Images

THE MAYOR OF New Jersey city has said gunmen targeted a kosher market during a shooting that killed six people.

The streets of Jersey City were filled with the sounds of heavy gunfire for hours on Tuesday, just across the Hudson River from New York City.

A police officer, three bystanders and two suspects died in the incident.

Mayor Steven Fulop said a review of security cameras show the gunmen targeted the market. He said two officers one block away responded immediately and engaged with the gunmen.

His public safety director has said terrorism was not suspected.

Steven Fulop / Twitter Steven Fulop / Twitter / Twitter

The dead officer, Detective Joseph Seals, 40, was credited by his superiors with having led the department in removing illegal guns from the streets in recent years, and he might have been trying to stop an incident involving such weapons when he was cut down by gunfire near a cemetery, authorities said.

Jersey City Police Chief Michael Kelly said the officer was trying to stop some “bad guys” near the cemetery. The gunmen then drove a stolen rental van to another part of the city and engaged police in a lengthy shootout from inside the market, where five more bodies were found.

“It’s a really tough day for the city of Jersey City,” Fulop said, adding that Seals “was one of the best officers for getting the most guns off the streets. He was a good cop”.

NJ Chiefs of Police / Twitter NJ Chiefs of Police / Twitter / Twitter

The bullets started flying early in the afternoon in the city of about 270,000.

Kelly said when police responded to the area of the kosher store, officers “were immediately engaged by high-power rifle fire”.

A video shot by a witness shows a police officer on the ground by a car, apparently wounded. Another officer goes to him, helps him up and the two run around a corner as gunshots ring out. Seconds later, as a police cruiser pulls up in front of the store, about a dozen shots are heard in rapid succession.

“Our officers were under fire for hours,” the chief said.

Inside the grocery store, police found the bodies of who they believed were the two gunmen and three other people who apparently happened to be there when the assailants rushed in, authorities said.

Police said they were confident the bystanders were shot by the gunmen and not by police.

Police after the incident took place.

The grocery is a central fixture in a growing community of Orthodox Jews who have been moving to Jersey City in recent years.

City public safety director James Shea said earlier on Tuesday that authorities believe the bloodshed was not an act of terrorism but that it was still under investigation.

The shooting spread fear through the neighbourhood, and the nearby Sacred Heart School was put on lockdown as a precaution.

Swat teams, state police and federal agents converged on the scene, and police blocked off the area, which in addition to the school and supermarket includes a hair salon and other shops.