China said on Sunday it was taking countermeasures against two Canadian institutions and 20 people involved in human rights issues concerning the Uyghurs and Tibet.

The measures, which took effect on Saturday, include asset freezes and bans on entry and the targets include Canada's Uyghur Rights Advocacy Project and the Canada-Tibet Committee, China's foreign ministry announces on its website.

Rights groups accuse Beijing of widespread abuses of Uyghurs, a mainly Muslim ethnic minority that numbers around 10 million in the western region of Xinjiang, including the mass use of forced labour in camps. Beijing denies any abuses.

China seized control of Tibet in 1950 in what it describes as a "peaceful liberation" from feudalistic serfdom. International human rights groups and exiles, however, have routinely condemned what they call China's oppressive rule in Tibetan areas.

For the two institutions, China said it is freezing their "movable property, immovable property and other types of property within the territory of China." It is freezing the property in China of 15 people in the Uyghur institution and five on the Tibet committee, banning them from entering China, including Hong Kong and Macau.

Canada recently announced sanctions on several Chinese officials, citing "grave human rights violations."

"Canada is deeply concerned by the human rights violations in Xinjiang and Tibet and against those who practise Falun Gong," Mélanie Joly, Minister of Foreign Affairs said in a statement issued earlier this month.

Calls to the Canadian embassy in Beijing went unanswered. Reuters did not receive an immediate response from the rights groups or Global Affairs Canada.