Jewish neighbourhoods in the New York metropolitan area have been placed on high alert after six people were killed following a shoot out at a Jersey City kosher market.
Investigators believe two assailants deliberately targeted the Jewish JC Kosher Supermarket and at least one of the suspects had reportedly published anti-Semitic and anti-police posts online.
The shoot-out began on Tuesday afternoon in Jersey City, New Jersey, directly across the Hudson River from lower Manhattan, when two assailants armed with high-powered rifles entered the store. A four-hour gun battle ensued.
The two suspects, reported to be a man and a woman, were killed in the attack along with three unnamed victims inside the kosher market.
A Jersey police officer, Joe Seals, was also killed earlier in the day when he approached the suspects in a nearby cemetery.
Detective Seals, 40, had been investigating a murder which took place in a nearby cemetery when he approached the assailants' van.
Law enforcement officers have not yet identified the attackers, but an official told the New York Times that one of the assailants had previously published anti-Semitic and anti-police material online, which they believe motivated the attack.
The official told the newspaper that detectives had also found a manifesto-style note inside the van used by the attackers, but the brief and "rambling" note had not offered any clear explanation for the shooting.
A police bomb squad was also investigating a possible explosive found in the stolen U-Haul vehicle the gunmen drove.
Jersey City police had initially said they believed the Jewish JC Kosher Supermarket was randomly singled out.
However, the city's mayor, Steven Fulop, later said that CCTV footage revealed the shooters had deliberately "targeted" the store.
Officials have since increased the police presence in Jewish communities in the area but Mr Fulop stressed that this was out of an "abundance of caution" and there was no indication of further threats.
Bill de Blasio, the mayor of New York City, said that he had also placed local police on high alert, in particular to protect Jewish residents.
"This tragically confirms that a growing pattern of violent anti-Semitism has now turned into a crisis for our nation," he said.
The initial confrontation between the suspects and police began near the Jersey City cemetery, about a mile away from the kosher market, where officers were investigating a previous murder.
Detective Seals was shot by the two assailants at the cemetery when he approached their U-haul van, which had been linked to a murder over the weekend.
Mr Fulop said on Wednesday that footage showed the suspects then drove slowly and deliberately to the market.
“The perpetrators stopped in front of there and calmly opened the door with two long rifles,” Mr Fulop said.
President Donald Trump was briefed on the incident and shared his condolences with the victims' families on Twitter. "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," he said.
The suspected anti-Semitic attack comes after an October 2018 massacre at the Tree of Life synagogue in Pittsburgh left 11 people dead in the deadliest attack on Jewish Americans in US history.
The suspect in that case, Robert Bowers, now faces the death penalty on multiple murder charges.