China's embassy in Ottawa warned Canada on Sunday to stop meddling in Hong Kong's affairs, saying that "the Canadian side should be cautious with its words and deeds."
Canada and the EU issued a joint statement Saturday saying the right of peaceful assembly is enshrined in basic law in Hong Kong.
Weeks of protests in the Chinese territory show no sign of relenting. The movement's demands include the resignation of the city leader, democratic elections and an independent investigation into police use of force.
Mainland Chinese police are holding drills in nearby Shenzhen, prompting speculation they could be sent in to suppress the protests.
The statement from the Chinese embassy in Ottawa says the "people of Hong Kong enjoy unprecedented democratic rights and a broad range of freedoms rarely seen across the world."
It also says the "relevant protests and demonstrations in Hong Kong have already deteriorated and evolved into extreme violence. In face of such severe violence and offences, no government with a sense of responsibility would sit idly by."
If Canada wants to voice a position, the statement added, it should "clearly condemn the violent criminal activities."
Relations between both countries have been at their worst since the Tiananmen Square massacre in 1989, following Canada's arrest of a Chinese tech executive who is facing fraud charges in the U.S.
China has detained two Canadians in apparent retaliation.