Authorities say bomb threats sent to dozens of businesses, schools, universities and other locations across Canada and the U.S. appear to be a hoax.

Over 10 threats have been made across Toronto, according to police. Details of the threats have not been made available.

King subway station in Toronto was also evacuated due to a bomb threat, but it was not immediately clear if it was similar to the other threats. It has since cleared.

Police across the GTA have also received several reports of bomb threats.

York regional police say they have responded to several unfounded email bomb threats demanding bitcoin sent to local businesses and individuals. Those who receive a threat are asked to contact police and not respond to the demand.

Several local businesses across Peel have received unfounded bomb threats, according to police. The emails demanded bitcoin payment in exchange for locations of the bombs.

Police in Halton say they have also responded to several email bomb threats demanding bitcoin similar to the ones across Canada Thursday. They have classified the threats as unfounded as well.

Provincial police also released a statement saying they are investigating several bomb threats across Ontario that were sent via email to businesses and institutions and demanded a payment in bitcoins.

Ottawa police say they responded to more than 10 bomb threats sent to local businesses and individuals in the Ottawa area where the sender also demanded a bitcoin payment.

All the threats have been deemed unfounded at this point. Police are encouraging anyone who receives an email, not to respond and to call police.

Winnipeg police say reports of bomb threats to businesses have been spread across the city and add while they are taking the threats seriously, none of them have been substantiated.

Calgary police have determined the multiple bomb threats sent out are a hoax and believe there is no threat to public safety. They responded to 15 incidents, but believe there are many more who received threats.

Five different companies in Montreal received threatening emails, but police say nothing suspicious was found at any of the locations.

Agent Jean-Pierre Brabant, a police spokesman, said the emails were the same as those received elsewhere in North America. They warned in imperfect English that unless $20,000 in Bitcoin was paid, a bomb would go off.

“Each call was taken very seriously,” Brabant said. “We sent police officers to the site, they searched the premises. We found nothing suspicious. There were no explosives.”

It was not necessary to call in the bomb squad, he added.

He said there was nothing connecting the companies, which were spread across the city.

“It appears to be a hoax, but we are not taking any chances,” Brabant said.

Manitoba and Alberta RCMP are working to determine the origin and validity of bomb threats made to multiple businesses in communities across the two provinces. Several received email bomb threats also demanding bitcoin payments.

All police services say they are aware of similar events happening across the continent.

Public Safety Minister Ralph Goodale says the government is aware of the multiple bomb threats and encourages anyone to report anything suspicious to local law enforcement.

Statement from the federal Public Safety Minister’s office on the bomb threats made in multiple cities across Canada #cdnpoli pic.twitter.com/TcshOEZHZx — Cormac Mac Sweeney (@cmaconthehill) December 13, 2018

Law enforcement agencies across the U.S. also dismissed the threats, which they said were meant to cause disruption and compel recipients into sending money and are not considered 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.

“We are currently monitoring multiple bomb threats that have been sent electronically to various locations throughout the city,” the New York City Police Department’s counterterrorism unit tweeted. “These threats are also being reported to other locations nationwide & are NOT considered credible at this time.”

Other law enforcement agencies also dismissed the threats, which were written in a choppy style reminiscent of the Nigerian prince email scam.

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.

The FBI didn’t immediately respond to a request for comment.

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 kilometres) 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.

“Organizations nationwide, both public and private, have reported receiving emailed bomb threats today,” Michigan State Police spokeswoman Shannon Banner said. “They are not targeted toward any one specific sector.”

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.”