Beijing, China - China urged countries on Friday to "stop spreading falsehoods" about its new ethnic unity law, after US lawmakers, the United Nations, and rights groups warned it threatens the freedoms of minorities.

The Law on Promoting Ethnic Unity and Progress came into force on Wednesday and aims to forge a "shared" national identity among ethnic groups by, for example, strengthening the status of Mandarin as the official language.

But overseas campaigners have warned that it will degrade the rights of minorities, like Tibetans and Uyghurs, that Beijing is accused of persecuting.

They also point to a clause stating that people can be held liable for violating the law even when outside China, saying it gives the Chinese government more justification for targeting its opponents abroad.

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At a press conference on Friday, Chinese foreign ministry spokesperson Guo Jiakun accused "certain countries" of making "sweeping generalizations (and) maliciously smearing China's ethnic policies."

"We urge the countries concerned to respect the basic facts, stop spreading falsehoods, and stop exploiting the so-called ethnic issues as a pretext for interfering in China's internal affairs," Guo said, without naming the countries.

Beijing consistently denies that it engages in rights abuses against any ethnic group and maintains that they all benefit from its policies of internal security and economic development.

Guo's comments came after nine US lawmakers voiced stern opposition to the law, pledging in a statement to keep speaking out against Beijing's bid to "legitimize its transnational repression."

UN rights chief Volker Turk has called for the law to be repealed, and Amnesty International has warned it will "further institutionalize... policies of forced assimilation."

Taiwan, which Beijing claims, has said the law will also expand "threats and intimidation against the people of our country and other nations."