Such moves are likely to chill the atmosphere in China for other diplomats and foreign businesspeople trying to work there.

But the detentions appear to be less a function of the personal activities of the three Canadians than retaliation for Canada’s arrest of Ms. Meng. She was picked up in Vancouver at the request of the United States while she was traveling to Mexico from Hong Kong.

At a bail hearing, Canadian prosecutors said Ms. Meng was suspected of helping banks violate United States sanctions against Iran. She is now out on bail while awaiting extradition to the United States, a process that could take weeks or even months.

The arrests have added a complicating layer to an already bitter trade war between the United States and China. They have drawn a sharp protest from the Chinese government, rattled financial markets and raised suspicions among Chinese officials that at least some Trump administration officials were trying to sabotage a trade deal.

Huawei and Ms. Meng, the daughter of the company’s founder, are part of China’s corporate elite, and her detention has brought huge domestic political pressure on President Xi Jinping.

Global Times, a newspaper aligned with the Chinese Communist Party, said that the impasse could be resolved quickly by Canada’s dropping all charges against Ms. Meng. “It is quite simple to end the crisis between China and Canada by giving back Meng’s complete freedom,” the newspaper wrote, most likely echoing the views of top officials.

There is so far no evidence that Ms. Meng’s arrest is anything more than a part of the Trump administration’s aggressive enforcement of the sanctions regime against Iran.