The gunmen who entered a kosher supermarket in Jersey City, N.J., on Dec. 10 and engaged in a deadly shootout with police deliberately chose the store, the city’s mayor said.

“Based on our initial investigation (which is ongoing) we now believe the active shooters targeted the location they attacked,” Mayor Steven M. Fulop said on Twitter on Tuesday night, Dec. 10. “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.”

The mayor’s tweet came hours after a news conference at which officials initially said there was “no indication of terrorism” or a hate crime.

Six people were killed, including a police officer and three civilians, in gunfire on Tuesday afternoon that ended with an hours-long shootout at the JC Kosher Supermarket on the west side of Jersey City. The officer had been shot earlier at a nearby cemetery trying to head off two suspects in a homicide. Those two young gunmen were killed in the supermarket shootout.

WNBC-TV in New York reported Wednesday that the shooters were David Anderson and Francine Graham. Anderson was once a follower of the Black Hebrew Israelite movement, sources told WNBC. Members of the community believe they are descendants of the tribe of Judah. Various groups vary widely in their connection to Judaism and Christianity.

Online postings connected to Anderson’s social media accounts contained anti-Semitic material. Investigators could not yet confirm if Anderson wrote the material himself.

On Wednesday morning, Dec. 11, in a new tweet, Fulop said, “Last night after extensive review of our CCTV system it has now become clear from the cameras that these two individuals targeted the Kosher grocery location on MLK Dr.”

He added in a second tweet, “I’m Jewish and proud to live in a community like #JerseyCity that has always welcomed everyone. It is the home of #EllisIsland and has always been the golden door to America. Hate and anti-Semitism have never had a place here in JC and will never have a place in our city.”

The dead police officer was identified as Det. Joseph Seals, a married father of five.

Two of the killed civilians were identified by Chabad.org as Leah Minda Ferencz, 33, who owned the store in the Greenville neighborhood of Jersey with her husband, Moshe, and Moshe Deutsch, 24.

Moshe Ferencz had left the store moments before the shooting to pray at the afternoon minchah service at the synagogue located next door, according to the report.

New York Mayor Bill de Blasio announced late Tuesday that following the incident across the Hudson River in Jersey City, the New York Police Department would go on high alert.

“Although there is no credible or specific threat directed against New York City, I have directed the NYPD to assume a state of high alert. Tonight, NYPD assets are being redeployed to protect key locations in the Jewish community,” he tweeted.

He added, “History teaches us how dangerous it is to ignore this kind of hateful pattern. We must stop anti-Semitism aggressively and decisively, and I call upon all New Yorkers to join in rooting out this threat.”

According to locals, the JC supermarket is the only kosher one of its kind in the Greenville area. It serves basic groceries, sandwiches and salads. Next door is Khal Adas Greenville, a building with a synagogue on a lower level and a yeshiva for children on the upper level.

“It’s a beautiful tight-knit community, very kind people, and it’s devastating that something like this happened,” said Rabbi Shmully Levitin, a Chabad rabbi who lives in Jersey City.

Greenville resident Chesky Deutsch has two children who attend the yeshiva next door to the grocery. Like many of his Orthodox neighbors, he recently moved to Jersey City from the Brooklyn, N.Y., area of Williamsburg because of more reasonable living standards.

“For the first few minutes, we didn’t know information about the school. Worried is an understatement,” he said about the moment he heard about the shooting. “My initial thought was, right away, is the community as a whole under some sort of attack? That was my initial fear.”

Deutsch said there is no tension between Jersey City’s Jewish community and its neighbors, which includes a large African-American population in Greenville.

“We get along very well with our neighbors,” he said. “Thank God, there was no incident whatsoever in the past.”

In a statement, Robert Bank, president and CEO of American Jewish World Service, said, “We are horrified and saddened by accounts of another attack on Jews in the United States — this time in a kosher market in Jersey City, NJ, as the evening shopping rush started. We are holding the Jersey City community in our hearts — especially the families of the five residents and one police officer who were killed. … We work every day to create a world in which people of all backgrounds can live with respect and dignity without the fear of hate or violence. We must all join together with people of every background to make our country and our world safe for all.”

Marcy Oster writes for the JTA global news source. JTA’s Josefin Dolsten and Gabe Friedman contributed to this report.