Bomb threats were called in at no fewer than 16 Jewish community centers in at least seven US states on Monday, prompting the evacuation of hundreds of students and staff.

Threats were reportedly received in Miami Beach and Jacksonville, Florida (see video above), as well as Rockville, Maryland; Nashville, Tennessee (see video below); South Carolina and California. Authorities were also investigating a bomb threat in a New Jersey JCC, a New York NBC affiliate reported.

The calls were prerecorded in some cases and live in others, with the caller using voice disguising technology, and likely came from a single source, said Paul Goldenberg, the director of Secure Community Network, the group affiliated with the Jewish Federations of North America that coordinates security for the Jewish community.

All the alerts were false, Goldenberg said, and designed to produce maximum disruption.

Similar threats were phoned in to several Jewish schools in Britain. Community officials responded by sending out a national alert that saw emergency procedures implemented at some institutes.

Police and emergency services in both countries combed through buildings, but no explosives were found.

It was not clear if the calls were a coordinated hoax.

Two community centers in Miami were evacuated following calls at around 11:00 a.m.

CBS Miami reported that a call from a local number was made to the Dave and Mary Alper Jewish Community Center.

Police were alerted and some 300 children evacuated to a tennis court close to the complex. Parents who arrived at the scene were prevented from approaching the children until police secured the building and made sure there were no explosives inside.

Another call was made to the Miami Beach Jewish Community Center on Pine Tree Drive, and officers gave the all clear at that location around an hour later. There were only a few people in the center at the time.

Screen capture of video showing people evacuated from a Jewish community center following a bomb hoax in Miami, Florida, January 9, 2017. (screen capture: YouTube/CBS Miami)

Screen capture of video showing people evacuated from a Jewish community center following a bomb hoax in Miami, Florida, January 9, 2017. (screen capture: YouTube/CBS Miami)

The Tennessean reported that a call was made to the Gordon Jewish Community Center at 10:30 a.m. prompting an evacuation of the building.

“We’ve taken all the necessary precautions that you would in a situation like this,” said Mark S. Freedman, executive director of the Jewish Federation of Nashville and Middle Tennessee, according to the report. “This is a threat against the entire community,” he said. “Everyone should be aware of that.”

WISTV reported a threat was made to the Katie and Irwin Kahn Jewish Community Center. A search found no evidence of a bomb.

The JCC Association of North America, the convening organization of JCCs across the continent commended the staff around the affected centers who “responded quickly, calmly and professionally by implementing well-practiced evacuation procedures and ensuring that no one was harmed,” said David Posner, the organization’s director of strategic performance, according to a press release.

Posner further thanked “federal and local law enforcement for their quick and thorough response today.”

The JCC Association said it was working with the Secure Community Network, which focuses on security for Jewish institutions throughout North America, and the Department of Homeland Security to determine the source of the calls.

In Britain, the Jewish Chronicle daily reported on its website that threats were telephoned in to schools in Roehampton, Ilford and Brent, all in London.

According to UK Jewish Chronicle, at one Jewish elementary school, pupils were told to go into the “sleeping lions” position — a safety precaution used in emergency situations. Other schools went into lock-down preventing anyone from entering or leaving the premises.

Pupils were not evacuated from any of the UK schools.

The Metropolitan Police said in a statement that “police were alerted at around 10:30 a.m. on Monday, 9 January, to phone calls made to schools in Roehampton, Ilford and Brent, in which bomb threats were made.”

“Police officers attended the schools. All three incidents were stood down a short time later. An investigation into the threat will be conducted.”

The Community Security Trust, the organization that oversees security for British Jewry, put out a national alert.

“A small number of Jewish schools across the country received bomb threats, as did a small number of non-Jewish schools,” the CST said.

“The Jewish schools followed security procedures, and CST and police immediately responded. All of the sites have been searched, and declared safe and secure. CST thanks school staff, pupils and parents for their calm response to these calls.”

JTA contributed to this report.