Authorities in Jersey City have confirmed multiple people are dead, including a police detective, following a shooting today in Jersey City.

The fallen officer has been identified as Det. Joseph Seals, a 15-year veteran of the department. He was married with five children. Seals helped get dozens of guns off of the streets as part of the department's Cease Fire Unit.

"We cried with the family. It's one of the hardest things you have to see in your entire life. I mean, nobody expected that Det. Seals would not return home. I'm sure his children expected him to return home and sometimes people don't appreciate the tough work that these police officers do every single day. Every day, they put on that uniform and they take their lives in their own hands and do it for the better part of a city like Jersey City," said Mayor Steven Fulop.

Although officials initially stated that the attack was not terror-related, Fulop tweeted Tuesday night that the location that was attacked had been targeted. He did not clarify further.

Jersey City Police Chief Mike Kelly said in a news conference the incident began at Bayview Cemetery around 12 p.m. He said there was gunfire between officers and the suspects, and it is believed that is where Seals was killed.

Kelly says the suspects took off in a stolen U-Haul van, which is being investigated by the bomb squad for possible incendiary devices.

The suspects then arrived at JC Kosher Supermarket on Martin Luther King Drive and began shooting inside.

Five additional people were found dead at the scene, according to Chief Kelly. He says two of those five are believed to be "bad guys."

The Hudson County Prosecutor's Office says two additional officers were also struck by gunfire. Officials say Ray Sanchez and Mariela Fernandez were the officers injured -- one in the shoulder and the other in the body. Both were treated and released from the hospital. A civilian was also injured.

A witness also told News 12 that two men with large guns wearing black got out of a truck and began shooting.

Several roads were shut down and all Jersey City schools were placed on lockdown after the shooting near Martin Luther King Drive and Bayview Avenue. All schools were systematically released at 4:15 p.m., according to Fulop.

SWAT teams responded to the scene, along with the NYPD bomb unit and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Heavy gunfire was heard during the standoff. Video shows a line of police officers armed with weapons pointed in several directions walking down the sidewalk.