The Chinese government charged two Canadian nationals with espionage on Thursday.

Both Canadians, former diplomat Michael Kovrig and businessman Michael Spavor, were arrested in December 2018. Kovrig stands accused of acquiring state secrets, and Spavor of stealing and selling state secrets. Chinese authorities claim that they now have solid proof that both men committed espionage.

Canada maintains that the arrests were retaliation for the detention of Meng Wanzhou, who the U.S. has charged with fraud for attempting to circumnavigate trade sanctions against Iran. Last month a Canadian judge ruled that Meng’s actions could constitute crimes in Canada, dealing a serious blow to her attempt to fight extradition to the U.S. Her attorneys had been arguing that Canada could not extradite her if her actions were not crimes in Canada.

Since the arrests of Kovrig and Spavor, China has vaguely acknowledged that the arrests were in response to Meng’s detention. The former Chinese Ambassador to China once public compared the arrests of Kovrig and Spavor to “self-defense.” To an extent, this contradicts a statement by Chinese Foreign Ministry spokesman Zhao Lijian, who said that the Chinese judicial system deals with cases independently. Canadian Prime Minister Justin Trudeau compared the two legal systems, saying that the Chinese government does not understand that politicians cannot interfere with or override the Canadian legal system.