OTTAWA -- Canada's strategy for navigating growing tensions with China is in disarray after Justin Trudeau fired his ambassador to Beijing.

The prime minister's office announced Saturday that ambassador John McCallum had been told to hand in his resignation -- just hours after he weighed in on a high-stakes extradition case for the second time in less than a week.

McCallum was quoted in a Vancouver newspaper as saying it would be "great for Canada" if the United States dropped its extradition request for Meng Wanzhou, the Huawei executive who was detained in Vancouver last month.

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He told StarMetro Vancouver on Friday that if the U.S. and China reach an agreement on Meng's case, the deal should include the release of Michael Kovrig and Michael Spavor, two Canadians currently detained in China for what many analysts say is revenge for the detention of Meng.

"We have to make sure that if the U.S. does such a deal, it also includes the release of our two people. And the U.S. is highly aware of that," McCallum told the Star.

That comment followed a statement McCallum issued Thursday, saying he misspoke earlier in the week when he discussed Meng's case with a group of Chinese-language journalists in Toronto, listing several arguments he thought could help her legal fight against extradition.

At first, Trudeau stood by his former minister. But McCallum's statements put the Liberal government in a touchy position. Trudeau has spent considerable effort and political capital over the past month telling world leaders that because of Canada's inherent respect for the rule of law, Canadian authorities had no choice but to detain Meng, and that the extradition process was not political.

McCallum's dismissal was too little too late for Conservative Leader Andrew Scheer, who had called on Trudeau to fire the ambassador as early as Wednesday, on the grounds that McCallum's remarks raised concerns about the politicization of the Meng case.

"Justin Trudeau should have fired his ambassador the moment he interfered in this case. Instead, he did nothing and allowed more damage to be done. More weakness and more indecision from Trudeau on China," Scheer tweeted Saturday.

"It should never have come to this."

Paul Evans, a China expert at the University of British Columbia, said this is the "most difficult and emotional moment in Canada-China relations in 30 years" -- since the Tiananmen Square aftermath.

The arrest of Meng may have been the immediate trigger but damage to Canada was almost inevitable because the country was already at the mercy of two much larger global forces: The clash between Chinese president Xi Jinping's growing authoritarianism and U.S. President Donald Trump's aggressive America First agenda.

"We're going deeper into the rabbit hole of Canada-China interactions. We are at a moment when we really don't know how deep that hole will get," Evan said in an interview the day before McCallum was fired.

Trust and respect have been thrown into question, and there's no more benefit of the doubt between Canada and China, he said.

By appointing McCallum to the Beijing post in the cabinet shuffle in 2017 Trudeau appeared to have the right person in place to push Canada's trade agenda with China even further.

Already an experienced cabinet minister, his biggest achievement was in the immigration portfolio in delivering on Trudeau's promise to bring tens of thousands of Syrian refugees into Canada.

McCallum also had strong personal ties to China. His wife has Chinese ethnicity and his three sons have Chinese spouses, something McCallum was fond of pointing out.

He also had a large Chinese constituency in his former federal riding in Markham, Ont.

Now that political investment is gone.

"In this hypersensitive era, we're all hyperventilating. Every twist and turn in this story, every comment just seems to put a little more salt in a wound that is getting deeper and not healing," Evans said.

In a brief scrum in Ottawa, Scheer accused the prime minister of damaging not only Canada's international reputation, but its chances of securing the release of Kovrig and Spavor.

He said McCallum's initial comments raised the spectre of political interference in the Meng case, and that by failing to act immediately, Trudeau undercut his own assurances that the case would be handled independently by the courts.

"This is, I think, part of a bigger problem. And that is Justin Trudeau's approach to diplomacy, where he thought he could conduct image-over-substance foreign affairs. And now Canadians are paying for his mistakes," Scheer said.

"Canadians' treatment in China is being affected by this."

The PMO declined to comment on exactly what led to the prime minister's change of heart about McCallum's fate.

In a news release announcing the ambassador's resignation, Trudeau thanked McCallum for nearly two decades of service. He noted that McCallum served as minister of immigration and refugees between 2015 and 2017, during the height of Canada's effort to resettle Syrian refugees.

In the wake of McCallum's resignation, Jim Nickel, deputy head of mission at the Embassy of Canada in Beijing, will represent the country in China as charge d'affaires effective immediately, the prime minister said.

With files from Mike Blanchfield