NEW YORK (CBSNewYork/AP) — New York Gov. Andrew Cuomo has ordered an investigation after the latest wave of bomb threats targeting Jewish community centers.

Cuomo said Jewish centers in Tarrytown, Staten Island, New Rochelle and Plainview, Long Island were targeted with bomb threats on Monday.

“These reprehensible and cowardly attacks are not limited to the Jewish community,” the governor said in a statement. “They are assaults on all New Yorkers and I vow that we will do everything in our power to catch those responsible for this wave of hate crimes.”

The JCC Association of North America says Jewish community centers and day schools in at least a dozen states also received bomb threats Monday. No bombs were found.

The group says it’s the fifth wave of bomb threats at Jewish institutions around the country since January. The group counts a total of 89 incidents in 30 states and Canada.

The Mid-Westchester JCC was one of the targets Monday. At the time, small children were inside the Scarsdale facility.

“It’s our turn. I honestly said, ‘it’s our turn,'” said Executive Director Karen Kolodny. “It’s a fear target, an attempt to make people unsettled and were not gonna let it defeat us.”

For now, many of the groups are being even more strict about security, doing whatever they can to ensure the safety of their members, CBS2’s Janelle Burrell reported.

“It’s a very difficult time just because these threats have not been credible,” said ADL regional director Evan Berstein. “They have a deep effect in the community. It effects people young and old and families and everyone in between and it’s something we must find an answer to.”

Police officers were stationed outside of the Mid-Island Y JCC in Plainview as students returned to class Tuesday morning.

CEO Rick Lewis said Monday’s threat was the first in the roughly 45 years that they’ve been at the location. He said he knows the institution is a target and that they routinely run bomb scare and lockdown drills.

“We were unfortunately waiting, it was only gonna be a matter of time,” Lewis said.

The center already had a regular security officer in place, and now Nassau County police are adding to that presence.

“It will be constant irregular, that way our residents feel safe,” Lt. Richard LeBrun said.

Rockland County Executive Ed Day said they are taking a proactive approach, like extra patrols at the JCC.

“The basics are obviously increase patrol, but there are many things that they are doing to ensure safety and security among houses of worship,” Day said.

The FBI and the Justice Department are also investigating the hoaxes.

“I think that these also come from national levels of government,” Bernstein told WCBS 880’s Sean Adams. “There needs to be that consistent speaking out. There needs to be a real plan.”

In Philadelphia, meanwhile, police are investigating after hundreds of headstones were knocked over at a Jewish cemetery during the weekend. The discovery came less than a week after similar vandalism in Missouri.

Attorney General Jeff Sessions called the vandalism and bomb threats serious, unacceptable behavior and said the department will “do what it can to assist in pushing back — and prosecuting anybody that we can prove to be a part of it.”

“We are a nation that is a diverse constituency, and we don’t need these kind of activities,” Sessions said.

Philadelphia Mayor Jim Kenney says authorities are doing everything possible to find those “who desecrated this final resting place.”

The Anti-Defamation League and a police union are offering a $13,000 reward for information leading to the arrest and conviction of those responsible.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)