Canadian Prime Minister Justin Trudeau is stepping up his pressure on China in a standoff over detainees, saying the country isn’t respecting the “principles of diplomatic immunity” in one case.

China seized a pair of Canadians, Michael Kovrig and Michael Spavor, on Dec. 10 in the aftermath of Canada’s arrest of a Huawei Technologies Co. executive, Meng Wanzhou. Trudeau’s comments are an apparent reference to Kovrig, who was on leave from his position with the Canadian foreign service and had been working for the International Crisis Group.

Trudeau, speaking Friday during a press conference in Regina, reiterated that Canada was operating under the “rule of law’’ in the Meng case, including granting her bail to allow her to be in her own home. He encouraged China to do the same.

“This is the way we live up to our rules within our justice system,” Trudeau said. “It is unfortunate that China has arbitrarily and unfairly detained two Canadian citizens, and indeed in one of the cases is not respecting the principles of diplomatic immunity.’’

China’s foreign ministry has said the Canadians are “suspected of activities endangering national security,’’ which allows authorities to hold them for as long as six months without charge or access to a lawyer. International Crisis Group said there was nothing secretive about Kovrig’s work, which involved writing public reports designed to prevent conflict.

Last month, Trudeau’s government stopped short of asserting diplomatic rights for Kovrig.

“The fact that Mr. Kovrig is an employee of my department means a lot of us know him and that adds another layer to the concern,” Foreign Minister Chrystia Freeland said on Dec. 12 during a press conference in Ottawa, but she didn’t say at that time he was entitled to diplomatic immunity.

Trudeau’s comments Friday came after China’s envoy in Ottawa accused Canada of “white supremacy” in the case, though Meng has been freed on bail while Spavor and Kovrig are still being held.

Canada has been rallying other countries to pressure China, though some, particularly the U.S., have been more outspoken than others. The U.S. has said China should release the Canadians. Canada arrested Meng after a request from the U.S., with which it has an extradition treaty.