The NYPD stepped up security at several synagogues and potential targets throughout the city Tuesday following the attack in Jerusalem that left five people dead, including several with dual-U. S. citizenship.

While there was no imminent threat to the city, Police Commissioner Bill Bratton said the department was closely watching several religious locations.

"The NYPD is following developments in Jerusalem closely and working with the FBI Joint Terrorism Task Force to monitor any further developments," Bratton said in a statement. "As of now, there is no specific credible threat to New York City. The NYPD has increased its attention to Synagogues and other symbolic locations around the city."

The deadly attack came as people were observing morning prayers in an ultra-Orthodox neighborhood in Jerusalem at about 7 a.m. The two Palestinian attackers used butcher knives and a gun to kill five people, including three U.S. citizens, and injure several others, authorities said.

There were about 30 worshippers, many wearing prayer shawls, in the temple at the time, according to the Israel Ministry of Foreign Affairs.

Police arrived shortly after and killed the two suspects.

Tuseday, Mayor Bill de Blasio said he was "horrified and heartbroken" by the attack.

"New York City stands in solidarity with Israel at this difficult time, and we hope and pray for a peaceful and secure future for all of its people," de Blasio said in a statement. "The NYPD is in close contact with its liaison post in Israel."

By Tuesday afternoon, officers stood inside and around entrances to city synagogues. A couple of uniformed officers stood guarding the entrance to Central Synagogue on 55th Street with a third standing near a stationed police car. At Temple Emanu-El on the Upper East Side, a pair of officers stood just inside the entrance.

A few uniformed officers normally stationed in front of The Consulate General of Israel in New York Tudor City stood by on Second Avenue. A spokesman for the consulate did not respond to a request for comment.

Sue Gold, the executive director of the Brooklyn Heights Synagogue, asked the security agency the temple uses to be extra vigilant "in terms of noticing unusual behavior and making sure everyone who comes in has an appointment" following the attack.

"As a community we share our concern and our outrage at this heinous act inflicted upon innocent worshippers at a very holy place," said Gold, 58. "But in this community, I don't feel that there is any reason to be panicked in this neighborhood."

Gold was in contact with the local police precinct as well, she said.

Rabbi Moshe Grussgott, whose Congregation Ramath Orah is on the Upper West Side, said he heard about yesterday's attack on the way to his own morning prayers.

"Unfortunately, I would say Jews have become all too used to being targets throughout our long history," he said. "America is probably the safest place, other than Isreal for Jews to be. But still, I'd say we're not immune anywhere."

While always vigilant, Rabbi Grussgott said he feels New York is a relatively safe place.

"I wouldn't say we live in fear because we refuse," he said. "It's a concern we have to deal with and we do deal with."

(With Lauren Holter)