Sarah McIver is being held in China for working illegally, Beijing said Thursday as the detention of yet another Canadian struck a note of fear around the world.

Ms. McIver, an Albertan teaching English in China, is under “administrative punishment,” the foreign ministry said.

She is the third Canadian being held after the arrest in Vancouver of Meng Wanzhou, chief financial officer of telecom giant Huawei Technologies Co., at the request of the U.S., which wants her extradited on allegations related to sanctions against Iran.

Ms. Weng has denied the accusations, which have not been proven in court, and is free on bail.

Ms. McIver’s detention does not appear to be further retaliation for Ms. Meng’s arrest, Prime Minister Justin Trudeau said Wednesday. Details obtained so far suggest this case is more of a routine matter, different from the Dec.10 detentions for former Canadian diplomat Michael Kovrig and entrepreneur Michel Spavor.

Mr. Kovrig and Mr. Spavor are being held on suspicion of “engaging in activities that endanger” China’s national security, Beijing says.

China has called Ms. Meng’s arrest political in nature, and critics have called the seizure of Canadians a retaliatory act that will ripple far beyond Canada’s borders.

“There is now a greater risk of NGOs, business people, academics and journalists being caught in the crossfire taking place between the U.S. and China,” said Shawn Shieh, who writes about NGOs in China and is a research fellow with the Chinese University of Hong Kong.

The risk, he said, is that other countries are also being “pulled in to this increasingly toxic relationship between the world’s two biggest economies.”

Of particular concern is the arrest of Mr. Kovrig, an analyst for International Crisis Group and former Canadian diplomat on unpaid leave.

He served at the Canadian embassy in Beijing and remains an employee of the Canadian government. In his time as a diplomat, he conducted political reporting, often on subjects that China considers sensitive. His detention has created worry about the safety of former diplomats who return to China.

Guy Saint-Jacques, the former Canadian ambassador to China, said he has considered whether it is safe to return to the country.

“I wonder myself if I were to go to China right now, would they say this is a great target for us?” said Mr. Saint-Jacques, who has been critical of China.

But, he said, “there is a lot at stake that could apply to all western countries.”

Mr. Kovrig’s status as a think tank analyst, for example, has raised concern about risk to the broader expatriate community in China, including people who for commercial and scholarly reasons have an interest in better understanding the intricacies of the country’s policies and conduct.

China’s state secrets laws give authorities broad powers, including the ability to retroactively criminalize actions that were lawful at the time.

“The very public manner of putting pressure on Canada to violate its own system of governance for the benefit of the Chinese Communist Party has opened peoples’ eyes to how China views international relations,” said Peter Dahlin, the director of Safeguard Defenders, which tracks China’s detention of people during investigations.

“The willingness to use innocent victims as a political tool will likewise raise alarm in the only community that is still supportive of closer interaction with China, namely the business community,” said Mr. Dahlin, who was himself detained and repeatedly interrogated in China for his work with a human rights organization.

The seizure of Canadians has also raised concern about their treatment in China, where authorities wield powers to subject people accused of violating national security measures to extensive interrogation for up to six months without access to a lawyer. Others similarly detained have said they were kept under the constant watch of guards, and threatened with execution by interrogators seeking confessions.

“There can be no doubt that Michael is tired and stressed,” said Hugh Pope, a spokesman for International Crisis Group, when asked about Mr. Kovrig’s condition.

“Others who have been arrested like this and were later released have typically had to undergo intensive questioning. The lights in their room aren’t ever switched off. There is no reason to believe it is otherwise for Michael. That is very worrying to us and to his family.”

The Globe and Mail, December 20, 2018