Police in both Nassau and Suffolk counties are stepping up patrols around religious centers today in the wake of what the FBI is calling a "terrorist attack" targeted at pro-Israeli demonstrators in Colorado Sunday.

The increased enforcement comes during the Jewish holiday of Shavuot, which began Sunday night and runs until tomorrow evening.

Police in Colorado and federal agents said a man with a makeshift flamethrower yelled “Free Palestine” and hurled an incendiary device into a group that had assembled to raise attention for Israeli hostages in Gaza on Sunday.

Eight people were injured, some with burns.

The suspect, Mohamed Sabry Soliman, 45, was booked into the Boulder County jail north of Denver and expected to face charges in connection with the attack, which the FBI was investigating as a terrorist act.

Nassau County police said in a statement Sunday night: "We are aware of what the FBI is calling a terror attack in Boulder, Colorado today. We are communicating with County Executive Blakeman as well as our partners in federal and local law enforcement. There is no threat to Nassau County."

Suffolk County Executive Ed Romaine and police Commissioner Kevin Catalina wrote: "The Suffolk County Police Department is monitoring the situation and will continue to share information with our law enforcement partners. While the department has received no information of similar threats locally, the department has increased our presence in the vicinity of religious institutions and houses of worship throughout Suffolk County. Antisemitism cannot be tolerated, and the men and women of Suffolk’s law enforcement community will continue to do all it can to protect every resident in this county."

Nassau County Police were in and out of the Mid-Island Y JCC in Plainview.

CEO Rick Lewis said he got on the phone with law enforcement last night within hours of the attack.

"We have good processes in place," Lewis said. "I don't have to hear the news on a Sunday night that, unfortunately, more people were injured for antisemitic reasons and have to worry about stepping up security."

The response calmed some nerves as people stopped by the community center today.

"Appreciative of all the security that's stepping up to make sure that everybody is protected," Plainview resident Vikas Bhambri said. "The broader community, the Jewish community and the people that use these facilities."

Officials on Long Island said they are continuing to monitor the situation.