Originally Published: 03 NOV 22 15:44 ET

Updated: 04 NOV 22 13:27 ET

By John Miller, Rob Frehse and Christina Maxouris, CNN

(CNN) -- An individual has been identified and interviewed in connection with a broad threat to synagogues in New Jersey, according to law enforcement sources, and the FBI in Newark tweeted on Friday that the source of the threat "no longer poses a danger to the community."

The person told authorities he does not like Jewish people and was very angry, but he indicated that he was not going to do anything harmful, the sources said.

An online posting with antisemitic comments in a forum frequented by extremists prompted an FBI alert Thursday night, CNN reported.

Authorities were alarmed because the posting was written as if an attack had already occurred, the sources explained. Similar writings have been posted by "active shooters" in incidents across the country just before their attacks.

That factored significantly into the urgency of locating him and also releasing the broad warning to the Jewish community, the sources said.

The online threat arrived at a moment of rising antisemitism in the US, as public incidents of bigotry have surfaced around the nation, from Florida to California.

It's unclear at this time what, if any, charges the individual connected to the New Jersey synagogues threat will face.

CNN has contacted the FBI for comment.

'Credible information of a broad threat'

On Thursday, the FBI in Newark tweeted it had received "credible information of a broad threat to synagogues" in the state.

"We ask at this time that you take all security precautions to protect your community and facility. We will share more information as soon as we can. Stay alert. In case of emergency call police," the post said.

In a second tweet, the agency said it was taking a "proactive measure" with that warning, while "investigative processes are carried out."

While no specific target, timing or plan was mentioned, the nature of the post created enough concern that the FBI decided to put a general warning out of an abundance of caution, the law enforcement sources said.

Part of that concern, the sources added, comes because of previous mass killings involving extremists who posted on social media, including the 2018 Pittsburgh synagogue killings, the deadliest attack on Jewish people on US soil; the 2019 mass shooting in El Paso, Texas, the deadliest attack on Latinos in modern US history; and the May massacre at a Buffalo supermarket, an attack which officials said was racially motivated.

Thursday evening, the FBI said it takes all threats seriously and was working with law enforcement to investigate the threat and was also "engaged with our faith based partners in the affected community."

New Jersey Gov. Phil Murphy said Friday, "This remains a tense time for our Jewish communities who are facing a wave of anti-Semitic activity."

Murphy said he was grateful to the FBI and other law enforcement partners "for their tireless efforts in mitigating the immediate threat to our Jewish synagogues."

"We will remain vigilant. We will take any and every threat with the utmost seriousness and we will stand up and stand shoulder to shoulder with our Jewish congregations."

Advice from a security company

The president of a company that provides security for hundreds of Jewish houses of worship and schools in the New Jersey and New York area has sent out guidance to clients to ask for additional security from law enforcement, he told CNN.

Synagogues should contact local law enforcement and "request not just increased patrols but actual manpower during prayers and other activities," said Joshua Gleis, of Gleis Security Consulting.

Gleis also advised synagogues not to conduct outdoor activities until further notice and to pull down exterior shades.

He also advised Jewish schools in the area to take similar actions until more information is available, as "any credible threat to a Jewish synagogue can become one to a Jewish school or community center."

The NYPD also said Thursday its Intelligence and Counterterrorism Bureaus were working with the Joint Terrorism Task Force and the FBI to "ensure the safety and well-being of every area that encompasses our Jewish citizens and synagogues here in New York City and the tri-state area."

Antisemitic comments across the country

Over the past few years, the US has seen a rise in antisemitic incidents, with 941 incidents in 2015 jumping to 2,717 tracked in 2021 by the Anti-Defamation League. On Thursday, the ADL said it was working with the FBI to address the credible threat and advised synagogues and Jewish organizations to "remain calm and in heightened state of alert."

The FBI's warning on Thursday comes amid continued reports across the country of anti-Jewish bigotry, including multiple antisemitic messages that appeared in public spaces in Jacksonville, Florida, over the weekend, and a group of demonstrators who hung banners over a Los Angeles freeway earlier in October showing support for antisemitic comments that were made by Kanye West. Photos also showed the group with their arms raised in what appeared to be the Nazi salute. Los Angeles officials condemned the incident.

West previously made a series of antisemitic outbursts, notably on October 8, when he tweeted he was "going death con 3 [sic] On JEWISH PEOPLE," and also that, "You guys have toyed with me and tried to black ball anyone whoever opposes your agenda," without specifying what group he was addressing, according to the Internet Archive's Wayback Machine records pulled by CNN.

His tweet was removed and Twitter locked his account. In an interview conducted after the controversial tweet, West told Piers Morgan that he was sorry for the people that he hurt but said he didn't regret making the remark.