Six people, including a police officer and three bystanders, were killed in a furious gun battle that filled the streets of Jersey City with the sound of heavy gunfire for hours, US authorities said.
The dead included two suspects, Jersey City Police Chief Michael Kelly said.
The shooting took place at two scenes, starting at a cemetery, where the officer was gunned down, and continuing at a kosher supermarket, where five more bodies were found, Kelly said.
"Our officers were under fire for hours," the chief said.
He would not say exactly what set off the shooting but that he believes the officer who was killed was trying to stop some "bad guys."
City Public Safety Director James Shea said that authorities believe the bloodshed was not an act of terrorism but that it was still under investigation.
Two other officers were wounded but were later released from the hospital, authorities said.
The bullets started flying early in the afternoon in the city of about 270,000 people, situated across the Hudson River from the Statue of Liberty.
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 included a hair salon and other shops.
Dozens of bystanders pressed against the police barrier to capture the action on their mobile phones, some whooping when bursts of fire could be heard.
Video shot by residents recorded loud volleys of gunfire reverberating along one of the city's main streets and showed a long line of officers pointing guns as they advanced, yelling to bystanders: "Clear the street! Get out of the way!"
"It's like firecrackers going off," said Andy Patel, who works at a liquor store about three blocks away.
"They were shooting like crazy. ... The cops were clearing everyone off the streets."
Just received a briefing on the horrific shootout that took place in Jersey City, NJ. Our thoughts & prayers are w/ the victims & their families during this very difficult & tragic time. We will continue to monitor the situation as we assist local & state officials on the ground.
— Donald J. Trump (@realDonaldTrump) December 10, 2019
President Donald Trump tweeted: "Just received a briefing on the horrific shootout that took place in Jersey City, NJ. Our thoughts & prayers are w/ the victims & their families during this very difficult & tragic time. We will continue to monitor the situation as we assist local & state officials on the ground."