Bomb threats targeted Jewish community centers in at least six states Monday, and some were made with prerecorded telephone calls, according to an official with the Jewish Federations of North America.

It's not clear why up to 20 Jewish community centers across the South and Northeast were targeted, said Richard Sandler, chair of the JFNA board of trustees.

"Some of the threats were robo-calls," said Sandler, adding that the number of threats was unusually high.

No additional details about the calls were immediately available. Some community centers were evacuated but no explosives were found, Sandler said.

Bomb threats also targeted Jewish community centers and schools in central Florida and Tampa last week, but Sandler said there was no apparent link between those threats and the calls received Monday.

Bureau of Alcohol, Tobacco, Firearms and Explosives spokeswoman Amanda Hils said in an email that the agency was aware of the threats and its field divisions were ready to assist state and local law enforcement.

Most of the centers have resumed normal operations, said David Posner, director of strategic performance at JCC Association of North America.

The Maitland Jewish Community Campus was evacuated Monday for the second time in a week because of a bomb threat. The complex includes a school, community center, a Holocaust museum and the offices of the Jewish Federation of Greater Orlando.

Bomb threats also were received at the Miami Beach Jewish Community Center and the Jewish Community Alliance of Jacksonville. A Miami-Dade Police bomb squad was dispatched to the Alper Jewish Community Center, where staff evacuated hundreds of children "as an abundance of caution," said Miami-Dade Police Detective Alvaro Zabaleta.

In Nashville, Tennessee, 225 people were evacuated from the Gordon Jewish Community Center and an adjacent school after a security guard received a bomb threat over the phone. Buildings were evacuated and authorities investigated similar threats in Atlanta; Tenafly, New Jersey; Columbia, South Carolina; and Wilmington, Delaware.

In Maryland, threats also were called into Jewish community centers in Baltimore and Rockville.

