The FBI has said none of the emailed threats should be considered credible.

A number of businesses in Dover and throughout the state were the targets of emailed bomb threats Thursday.

The FBI has said none of the emailed threats should be considered credible.

"The FBI is 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," Carrie Adamowski, public affairs representative for the bureau's Philadelphia field office, said.

"As always, we encourage the public to remain vigilant and to promptly report suspicious activities which could represent a threat to public safety," she added.

Locally, Delaware State Police spokesman Master Cpl. Melissa Jaffe said she was working to determine what businesses and public institutions may have been contacted.

The Delaware incidents were, she said, "The same type of general threats made nationwide."

The threats were similar to a spate of telephoned warnings made in 2016. 

Because they are sent in via emails whose origins can be easily hidden, such cases are difficult to track down and solve, Jaffe added.

Master Cpl. Mark Hoffman of the Dover Police Department said some concerns in the city also had received the emails, although he also was not prepared to name them.

According to the FBI and Bureau of Alcohol, Tobacco and Explosives, threats were made in Miami, New York, San Francisco, Seattle, Washington, D.C. and other cities.

The Cedar Rapids, Iowa, police department posted the text of a threat email on their website, with the FBI acknowledging identical emails had been reported nationwide.

The email, in poorly worded English, says an explosive had been placed inside the business and demanded $20,000 in Bitcoin to not detonate the device. The bomber’s alleged accomplice would be watching the building and would detonate the bomb early if the demands were not met.

Similar threats also have been received in Canada, according to various news sources.

NOTE: This story has been updated since its original posting to reflect additional data from the Delaware State Police.