Hong Kong (CNN) Chinese authorities have formally arrested two Canadians who have been held in detention for five months on suspicion of espionage, in a move likely to increase tension between Ottawa and Beijing.

Former diplomat Michael Kovrig and businessman Michael Spavor were detained on December 10, accused of gathering and stealing "sensitive information and other intelligence" since 2017.

Their detainment came shortly after the arrest of a Chinese executive in Vancouver, a move which infuriated Beijing and sparked a diplomatic crisis.

Chinese Foreign Ministry spokesman Lu Kang said Thursday the arrest of Kovrig and Spavor had been approved by "Chinese prosecutorial authorities" and asked Canada to stop "making irresponsible remarks on China's rule of law."

"Michael Kovrig was recently arrested for spying on state secrets and intelligence for foreign entities, and Michael Spavor was recently arrested for stealing and unlawfully providing state secrets to foreign entities," Lu said.

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