The trial of another Canadian citizen charged with espionage began Monday (March 22) in a Beijing courthouse.
Former diplomat Michael Kovrig is the second of two Canadians tried for spying in China this month - following the trial of businessman Michael Spavor on Friday (March 19).
Both were arrested over two years ago.
The trial comes just days after the United States raised concerns over their case at tense bilateral talks with China in Alaska.
Both trials were held behind closed doors, for what Beijing said were national security reasons.
Jim Nickel, the Deputy Head of the Canadian embassy in Beijing, was present outside the courthouse.
He said he had been repeatedly denied access to the hearing.
"He's been arbitrarily detained, and now we see that the court process itself is not transparent. We're very troubled by this. We have with us today some 28 representatives of the embassies here in Beijing, they're representing 26 different countries, in support, showing solidarity, and support, and lending their voice too, for the immediate release, of Michael Kovrig."
Dubbed the 'two Michaels' in the Canadian press, the pair were arrested soon after Canadian officials detained telecoms giant Huawei's CFO, Meng Wanzhou on a U.S. warrant.
Beijing has said that the incidents are not linked.
Meng remains under house arrest in Vancouver as she fights extradition to the United States.
While the country's courts have yet to reach a verdict in either trial, the country has a conviction rate of over 99%.