At the same time, the US has been leading a campaign to get countries to block Huawei, which wants to roll out fifth-generation Internet technology worldwide, citing fears that the Chinese Government could use the technology for spying.
The arrest of Meng, who is the daughter of Huawei's founder, has incensed China. The company, which is the world's largest maker of telecommunications equipment, is a national champion in China, encapsulating the rags-to-riches "Chinese dream" but also exemplifying how companies can move up the value chain.
Meng is confined to her home in Vancouver while she fights the extradition case.
Kovrig and Spavor have been detained in Beijing and Dandong, on the North Korean border, respectively. They have been denied access to their families and to lawyers, and have been kept in cells with the lights on round the clock. Consular officials have been permitted to make several short visits to both men.
Kovrig, who was based in Hong Kong, has travelled to China frequently since 2017 with a regular passport and a business visa, the Chinese commission said. He "is suspected of spying and stealing national secrets for foreign agents and his behaviour has severely violated Chinese law," it said.
Spavor had been running Paektu Exchanges, a company based in Dandong that he founded to promote cultural, sporting and business contacts with North Korea. He was involved in organising former basketball star Dennis Rodman's trip to Pyongyang in 2013 and spent hours with North Korean leader Kim Jong Un during that visit.
The authorities "stressed that China is a country run by the rule of law and the country will resolutely crack down on criminal activities that jeopardise national security," the report on the commission's website said.
The announcement came after Canada said that it would move ahead with an extradition hearing for Meng, a sign that its Justice Department thinks there is "sufficient evidence" to formally proceed.
Meng will appear in a Vancouver court this week to schedule the date of the hearing, the department said.
China's Foreign Ministry again urged the United States to drop the extradition request.
"We are reiterating our demand to the US to cancel the arrest order and extradition request for Ms Meng, and urging Canada to free her immediately and ensure her safe return to China," spokesman Lu Kang said.
"Canada and the US abused their extradition treaty in arbitrarily taking coercive measures against Ms Meng.
"It is an outright violation of the legitimate rights and interests of Chinese citizens. This is a serious political incident," he said in a statement.
In its latest broadside against Canadian authorities, the nationalist Global Times newspaper said that the case against Meng "was a US political game against Huawei, forged to look like a lawsuit."
"We hope there will eventually be a turnaround in Meng's case, or the spirit of justice will prevail and stop the US and Canada from manipulating the judicial system," the paper wrote in an editorial. "We also hope the two governments will realise they are playing a dirty game, which will make them find a legal reason to revoke the case."
US President Donald Trump has suggested that he could discuss the cases against Huawei and Meng as part of a broader trade deal with China, prompting criticism that he was politicising what should be a strictly legal decision.
Separately, Meng is suing the Canadian Government, charging that border security and police officers detained, searched and interrogated her before advising her that she was under arrest. The authorities interrogated her "under the guise of a routine customs" examination and used the opportunity to "compel her to provide evidence and information," the lawsuit says, according to AP.
