A Chinese court has upheld a death sentence against Canadian citizen Robert Schellenberg.

Schellenberg has been detained in China since 2014, when he was accused of attempting to smuggle 225kg of methamphetamine to Australia. He has maintained his innocence. In December 2018 he was sentenced to 15 years but after he appealed a retrial was ordered and the Dalian intermediate people’s court instead ordered his execution.

His case is one of at least two involving Canadian detainees expected to hear a result as early as Tuesday, in what observers and foreign governments have labeled “hostage diplomacy” by Chinese authorities over an ongoing extradition hearing in Canada for a Huawei executive wanted in the US.

On Tuesday morning a Chinese court in Shenyang rejected Schellenberg’s appeal against his death sentence on drug smuggling charges. According to the Globe and Mail, the decision is expected to prompt a mandatory review of his case by China’s equivalent of the supreme court.

The court said the facts presented in the earlier trial were clear and the evidence “reliable and sufficient”.

“The conviction was accurate, the sentence was appropriate, and the trial proceedings were in accordance with the law,” it said.

Separately, another court is reportedly expected to deliver a sentence against Canadian Michael Spavor, a businessman who was charged with espionage alongside former diplomat Michael Kovrig and tried in secret in March after more than 830 days in detention.

The arrest of the men and the retrial of Schellenberg have been linked to Canada’s arrest of Chinese Huawei executive Meng Wanzhou, which occurred just days earlier.

Meng was arrested at Vancouver airport on a US warrant in late 2018 over allegations she committed fraud by misleading HSBC about Huawei’s business dealings in Iran. The US alleges Huawei used a Hong Kong shell company to sell equipment to Iran, in violation of sanctions.

The ongoing extradition hearing in Canada has sent Canada-China relations plummeting.

Beijing denies its prosecution of Schellenberg, Spavor and Kovrig are retaliation for Meng’s arrest. Canada’s prime minister, Justin Trudeau, has said the charges against the two Michaels are “trumped-up” and that Chinese officials were “very clear” the cases were connected.

Canada’s ambassador to China, Dominic Barton, attended the Schellenberg ruling, and said outside court that Canada condemned the verdict “on all possible terms”.

“We call on China to grant Robert Schellenberg clemency. We’ve expressed our firm opposition to this cruel and unusual punishment and we… will continue to express that to the Chinese authorities.”

Barton told the Globe and Mail it was no coincidence that it and the expected Spavor verdict were happening as Meng’s case drew to an end.

“It’s very clear this is being used as leverage to try get madam Meng sent home to China,” said Margaret McCuaig-Johnston, a senior fellow at the University of Ottawa’s graduate school of public and international affairs.

McCuaig-Johnston said Chinese authorities were sending the message that there were still ‘outs’ for the detained Canadians depending on Meng’s outcome: Schellenberg has one final case review, and the two Michaels have not yet been convicted.

She noted Canada’s court could rule against extradition to the US, although that usually only occurred if someone was too sick to travel or was unlikely to get a fair trial in the destination state. If it rules Meng should be extradited, the decision then goes to Canada’s minister of justice for approval, which is where the situation got “politically challenging” for Ottawa.

“The government of China is quite desperate now that she not be sent to the US, so they feel their one chance of getting her home to China is pressuring Canada to give her up.”

Schellenberg’s sentencing prompted a travel warning from the Canadian government, over “the risk of arbitrary enforcement of local laws”.

The two Michaels were tried in secret in March, at a two-hour hearing after which no verdict or sentence was announced. Canadian diplomats were denied access to the trial.

China’s court system is notoriously opaque, with conviction rates of about 99%, and successful appeals are very rare.