RIVERSIDE, Calif. (KABC) -- Several SoCal law enforcement agencies were investigating bomb threats emailed to organizations and businesses as authorities from across the country fielded similar threats, deemed by most as a hoax.
The Riverside County Sheriff's Department said bomb threats were emailed to several businesses in the area as well as other counties. None of the threats have been substantiated.
The department said it is just one of several law enforcement agencies "experiencing an influx of email threats."
Chino police told Eyewitness News that it is also investigating some emailed bomb threats, though they've also said the threats do not appear credible. The El Monte Parks and Recreation Department also confirmed it received a threat via email.
Threats were confirmed in Palm Desert, Palm Springs, Temecula, Lake Elsinore, Redlands, Ontario, Montclair and Rancho Cucamonga.
In Orange County, Garden Grove police said the agency received several calls around 11:15 a.m. from local businesses reporting a bomb threat by email.
San Francisco police are also investigating threats made to multiple locations in the city.
The Jewish Community Center in San Francisco was evacuated due to a threat. In addition, a building on the 200 block of Brannan Street was evacuated.
Police in New York and Massachusetts are also monitoring multiple bomb threats at separate locations.
The Bronx Science High School was evacuated after a bomb threat was received by phone. A call came into the school saying a pipe bomb would explode in 20 minutes, and the NYPD cleared the school before the Emergency Service Unit determined there was no credible threat.
The threat seemed to fit the pattern of others deemed not credible. Some of the emails had the subject line: "Think Twice." The sender claimed to have had an associate plant a small bomb in the recipient's building and that the only way to stop him from setting it off was by making an online payment of $20,000 in Bitcoin.
Up to a dozen emails were sent to businesses/schools in Washington, D.C. alone. Bomb threats were also made to several locations in the Chicago area, including Aurora City Hall, the Aurora Library and Rush Copley Medical Center.
The FBI issued the following 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."
Law enforcement agencies across the country have dismissed the threats, which they said were meant to cause disruption and compel recipients into sending money and are not considered credible.
The Palm Beach County, Florida, sheriff's office and the Boise, Idaho, police said they had no reason to believe that threats made to locations in those areas were credible.
Across the country, some schools closed early and others were evacuated or placed on lockdown because of the hoax. Authorities said a threat emailed to a school in Troy, Missouri, about 55 miles (88 kilometers) northeast of St. Louis, was sent from Russia.
The bomb threats also prompted evacuations at city hall in Aurora, Illinois, the offices of the News & Observer in Raleigh, North Carolina, a suburban Atlanta courthouse and businesses in Detroit.
Penn State University notified students via a text alert about threats to a half-dozen buildings and an airport on its main campus in State College, Pennsylvania. In an update, the school said the threat appeared to be part of a "national hoax."
Officials at Columbine High School in Colorado were dealing Thursday with a bomb threat of a different sort. Students were being kept inside for the rest of the school day after someone called in a bomb threat against the school.
City News Service, KGO-TV, WABC-TV, ABC News and Associated Press contributed to this report.