In a letter published by The Hill Times newspaper, China's ambassador to Canada Lu Shaye also criticized the "groundless" detention of a top Chinese tech executive at the request of the United States.

China detained former diplomat Michael Kovrig and businessman Michael Spavor last month, accusing them both of activities that "endanger China's security" -- a phrase often used by Beijing when alleging espionage.

The arrests are thought to be in retaliation against Canada's December 1 arrest of Huawei vice president Meng Wanzhou, who is accused of violating Iran sanctions.

"It's understandable that these Canadians are concerned about their own citizens. But have they shown any concern or sympathy for Meng after she was illegally detained and deprived of freedom?" Lu wrote in the Ottawa newspaper.

"It seems that, to some people, only Canadian citizens shall be treated in a humanitarian manner and their freedom deemed valuable, while Chinese people do not deserve that," he said.

"The reason why some people are used to arrogantly adopting double standards is due to Western egotism and white supremacy."

Canadian Prime Minister Justin Trudeau and US President Donald Trump in a telephone call on Monday denounced the "arbitrary" detentions of Kovrig and Spavor.

Australia, Britain, France, Japan, Germany and the European Union have also made statements in support of Canada.

Meng is currently living in a luxury home in Vancouver after being released on bail pending the outcome of an extradition hearing.

She is required to wear an electronic anklet to monitor her movements and has an 11:00 pm to 7:00 am curfew.

Meanwhile, a group of Canadian parliamentarians visiting China this week complained to officials that Kovrig and Spavor have been granted few consular visits, denied access to lawyers, and remain in "completely unacceptable" detention conditions.