An apparent bomb threat hoax demanding a payment in Bitcoin was circulated by email on Thursday, forcing local police departments to mobilize and evacuations at businesses, hospitals, government offices, news outlets, and schools across the country—including in California, Florida, Illinois, Iowa, New York, Oklahoma, Massachusetts, and Michigan.

The FBI said in a statement, “We are aware of the recent bomb threats made in cities around the country, and we remain in touch with our law enforcement partners to provide assistance. As always, we encourage the public to remain vigilant and to promptly report suspicious activities which could represent a threat to public safety.”

Several local police agencies have said that authorities have found no credible evidence that the threats contained in the messages are “authentic.”

SCROLL TO CONTINUE WITH CONTENT