China carrying out 'intense' global attack on rights: HRW

China is using its economic and diplomatic might to carry out the "most intense attack" ever on the global system for protecting human rights, a leading campaign group said Tuesday.

Human Rights Watch made the allegation in its annual report, launched in New York two days after executive director Kenneth Roth was barred from entering Hong Kong to release it there.

The NGO accuses President Xi Jinping's government of overseeing "the most brutal and pervasive oppression that China has seen for decades," including building a "nightmarish surveillance system" in Xinjiang province.

To fend off global efforts to hold it to account, Beijing has "significantly increased" efforts to undermine the international institutions created in the mid-20th century to defend human rights, HRW said.

"Beijing has long suppressed domestic critics. Now the Chinese government is trying to extend that censorship to the rest of the world," Roth said in the 652-page report.

"If not challenged, Beijing's actions .