Bomb threats were made to 19 Jewish community centres in America on Monday - some of which have been used to host nursery schools and senior citizen groups.
The threats - some of which appear to have been pre-recorded - took place across several different states and included Jewish centres in Florida, Miami, Maryland, Tennessee and South Carolina.
Police arrived to search properties after callers claimed explosives were planted inside the buildings.
In Miami, two community centres were evacuated, including 450 students and 70 teachers at one JCC, while police conducted searches.
All the incidents turned out to be hoaxes - but police are continuing to investigate what appears to be a planned operation to target so many different Jewish centres on the same day.
Law enforcement officials are investigating the possibility that the threats came from a single source.
