Jewish community centers in several states have been targeted with bomb threats, but authorities said it was not immediately clear whether the threats were linked.

A 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.

The Maitland Jewish community campus was evacuated on 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.

Police said no explosives were found after bomb threats 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” after a bomb threat was called in, said Alvaro Zabaleta, a Miami-Dade police detective.

“As a community, we must always be vigilant when it comes to security,” the Greater Miami Jewish Federation’s director of community security, Brenda Moxley, said in an email.

In Nashville, Tennessee, police responded to the Gordon Jewish community center after a security guard received a bomb threat over the phone.

No explosives were found, but 225 people in the building and an adjacent school were evacuated, said Mark Freedman, executive director of the Jewish Federation of Nashville and Middle Tennessee.

In Delaware, the Siegel Jewish community center in Wilmington was evacuated after a bomb threat was called in.

Buildings were evacuated and authorities investigated similar threats in Tenafly, New Jersey, and Columbia, South Carolina. In Maryland, threats were also called into Jewish community centers in Baltimore and Rockville.

Last week, bomb threats also targeted two Jewish preschools in Tampa and an Orange County Jewish community center.