JERSEY CITY (CBSNewYork) – A police officer was among six killed in a lengthy gun battle in Jersey City Tuesday.

Watch continuing coverage on CBSN New York

The two suspects were also killed, along with three civilians. Their bodies were found in a kosher grocery store at Bayview Avenue and Martin Luther King Boulevard after an intense, hours-long shootout with police. Jersey City Police Chief Michael Kelly said police believe the three civilians killed in the grocery store were shot by the suspects.

Photos: Active Shooter Scenes From Jersey City’s Deadly Gunfight

It began at roughly 12:30 p.m. at the Bay View cemetery at Garfield Avenue. The suspects were spotted at the cemetery in a stolen rental van. Kelly said he believes Det. Joseph Seals – who was part of the unit responsible for removing guns from the street – was attempting to interdict weapons in the van when he approached the suspects, and they opened fire.

Det. Seals was hit. He was rushed to the hospital, but did not survive.

The suspects then drove about a mile to the grocery store in the middle of a residential neighborhood, where more shots were fired.

Watch: Jersey City Police Chief Michael Kelly On Deadly Shootout

“Units responded and were immediately engaged by high powered rifle fire,” Kelly said. He said responding officers set up a perimeter and called for mutual aid from other law enforcement agencies.

“Just about all the folks that were within earshot of us responded,” Kelly said. “[We] continued to take gunfire for hours. Our officers were under fire for hours. Two more police officers were hit by gunfire. One sustained an injury to the shoulder. One sustained another injury to the body. Those officers have since been released from the hospital.”

He identified the injured officers as Ray Sanchez and Mariela Fernandez. Kelly said “hundreds” of shots were fired during the gun battle.

Watch: Mayor Steven Fulop Briefing On Jersey City Shooting

Mayor Steven Fulop called Det. Seals “one of our best police officers.” He had been on the job for more than 15 years and was assigned to the city’s “cease fire” unit, responsible for removing guns from the street.

“Dozens and dozens of handguns he’s responsible for removal from the street,” Kelly said. “We believe that he was killed while trying to interdict these bad guys at that other location on Garfield Avenue.

This is Det Joe Seals who was killed in the line of duty today! He was a husband and father of 5. He is a #Hero and died protecting the citizens of Jersey City! God Bless his family and all of the JCPD members! #JerseyCityShooting @JCPoliceDept pic.twitter.com/pvs62bb0af — NJ Chiefs of Police (@NJSACOP) December 10, 2019

Seals leaves behind a wife and five children. Kelly and Jersey City Mayor Steven Fulop visited with them after the shooting.

“We cried with the family. It’s the one of the hardest things that you ever have to see in your entire life. Nobody expected, I’m sure, Detective Seals not to return home. I’m sure his children expected him to return home. Sometimes people don’t appreciate the tough work these police officers do every single day,” Fulop said.

Just provided a brief update to press as scene is still active but secure. 2 officers struck by gun fire. One of the officers tragically has given his life. 2 other officers receiving medical treatment at the jcmc for injuries unrelated. Please keep these officers in your prayers — Steven Fulop (@StevenFulop) December 10, 2019

Jersey City Director of Public Safety James Shea said there was no indication the incident was terror-related. Kelly said the stolen U-Haul “may contain an incendiary device” and has been taken for examination by the bomb squad.

Tuesday night, Mayor Fulop tweeted that officials now believe the suspects targeted the kosher market and that the community may see an increase in police presence though there’s no indication there are any further threats.

Based on our initial investigation (which is ongoing) we now believe the active shooters targeted the location they attacked. Due to an excess of caution the community may see additional police resources in the days/weeks ahead. We have no indication there are any further threats — Steven Fulop (@StevenFulop) December 11, 2019

Schools in the area were placed on lockdown during the shootout. The lockdown was lifted at 4:15 p.m. Officials said all children were safe and accounted for. Nonetheless, parents were nervous.

“Pretty anxious. I got a call from the school, I got a call from the kids that they’re safe,” a parent named Juan told CBS2’s Jessica Layton.

Watch: Barrage Of Gunfire Rings Out During Jersey City Shootout

During the height of the gun battle, dozens of shots could be heard going off as police engaged the suspects in the vicinity of Martin Luther King Drive and Bayview Avenue. Officers wearing tactical gear and carrying long guns swarmed the scene in armored vehicles. New Jersey State Police said they deployed canine units, the bomb squad, aviation units and tactical squads among other resources to the scene. The NYPD’s Emergency Services Unit also was brought in to assist.

JUST IN: Massive police response right now in New Jersey after active shooter was called in possible hostage situation. Stay tuned! pic.twitter.com/QXKRoUs0v3 — Mark Kennedy 🇺🇸 (@RealMarkKennedy) December 10, 2019

“I got caught in a one way street with a bunch of cars and I was wondering why nobody was moving. And all of a sudden I heard it. All the shots started. Shots started ringing out. When I heard it, I see people running. I got out of the car and I see cops ducked down, and cops getting out of the way,” witness Brian Clark said.

Watch: Witnesses Describe Jersey City Shootout

“And I’m wondering why, what the hell? So I get out of my car and I see it, and I heard it – pow pow pow pow pow – then I realized I was in a shootout. I never heard that many shots in my life. It was like I was in a war zone,” Clark added.

“We were ready to take lunch and all of a sudden we heard a lot of gunshots,” a witness named Carlos told CBS2’s Alice Gainer. “I heard over 200 gunshots fired.”

Gov. Phil Murphy and President Donald Trump were both briefed on the incident. Murphy visited the scene after the shootout. Trump called the shooting “horrific” and said his thoughts and prayers were with the victims and their families.

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

Jersey City Medical Center was placed on lockdown due to the shooting.

New Jersey Transit Police reported Hudson Bergen Light Rail was suspended in the area, along with all bus service on the West Side Branch. New Jersey Turnpike exit ramps at Interchange 14B were closed because of the incident.

Today is a horrific day. Officers have come under attack and we have several wounded. Our hearts are heavy and the violence is not over. We need prayers. — New Jersey State PBA (@NJSPBA) December 10, 2019

“Today is a horrific day. Officers have come under attack and we have several wounded. Our hearts are heavy and the violence is not over,” the New Jersey State PBA tweeted. “We need prayers.”

CBS2’s Jessica Layton reports local schools will open on a delayed scheduled Wednesday. Classes at Jersey City public schools will begin at 10 a.m.

Traumatic day for local school kids too. District just posted a delayed opening for tomorrow. @CBSNewYork https://t.co/93T2nKlnbS — Jessica Layton (@JLaytonTV) December 11, 2019

Check back soon for more information on this developing story.