Huawei has worked with dozens of security contractors to develop surveillance products, some of which were touted as being able to identify a person’s ethnicity or to help suppress potential protests, according to company marketing documents that shed light on a little-publicized corner of one of China’s most valuable tech empires.

The revelation this week of Huawei’s role in testing artificial-intelligence surveillance technology — including a face-scanning camera system that could send a “Uighur alarm” to police if it detected a member of the minority group — has sparked an international backlash against the tech giant, including from a French soccer star who publicly ended his work as a Huawei brand ambassador and urged the company to “condemn this mass repression.”

Huawei representatives said the document outlining the “Uighur alarm” system, discovered on the company’s website by the research organization IPVM and first reported by The Washington Post, used language that is “completely unacceptable.” “It is not compatible with the values of Huawei,” a representative told the BBC. “Our technologies are not designed to identify ethnic groups.”

Yet products made by Huawei with four other partner companies were also advertised to have ethnicity-tracking capabilities, according to Chinese-language marketing materials posted on a public Huawei website where the material could be downloaded by anyone who registered an account. After The Post approached Huawei for comment, the site briefly became inaccessible. When it returned, the number of product collaborations detailed there had dropped from more than 2,000 to 38.

“We take the allegations in the Washington Post’s article very seriously and are investigating the issues raised within,” a Huawei spokesperson said in a statement to The Post.

The statement continues: “We provide general-purpose ICT [information and communications technology] products based on recognized industry standards. We do not develop or sell systems that identify people by their ethnic group, and we do not condone the use of our technologies to discriminate against or oppress members of any community.”

Huawei and its partners have provided some of these surveillance products to authorities in the northwestern Xinjiang region, where the Chinese Communist Party has sought for decades to control and assimilate the Uighurs, a Turkic ethnic minority, most recently through a massive “reeducation” program. Among them, according to documents from Huawei’s website, was a facial recognition system used by police in the Xinjiang capital, Urumqi, and a highway surveillance camera system for the region.

Several of the companies on Huawei’s partners list were sanctioned last year by the U.S. Commerce Department, because of concerns that they contributed to state surveillance of Uighurs. Those companies included SenseTime, Megvii, iFlytek and Yitu Technology.

Maya Wang, a senior China researcher at the advocacy group Human Rights Watch, said Huawei has become an important player in surveillance technology, thanks to its vast assortment of servers, cameras, cloud-computing systems and other back-end technical tools.

“Mass surveillance is a really big business for the ecosystem of companies in this space,” Wang said, and major companies have “benefited tremendously from the security surveillance spending from the Chinese government.”

Huawei’s partnerships reflect the ongoing expansion of surveillance in China, where top officials have called for police to use big data to fight crime, under the slogan, “One Person, One File,” a phrase signifying the use of disparate information streams, from surveillance footage to Internet chat history, to better track individuals. Companies have rushed to stake a claim to this vast, lucrative new market.

In the United States, police have also sought to use some technologies, such as facial recognition, to investigate crimes but have stopped short of publicly adopting technologies to analyze people’s voices and ethnicities. In the wake of nationwide protests over the summer against police abuse, Microsoft, Amazon and IBM banned police from using their facial recognition technology. (Amazon founder and chief executive Jeff Bezos owns The Post.)

Protests on the scale of Black Lives Matter would be nearly impossible to organize in mainland China — partly because of these very surveillance technologies. One of the products jointly offered by Huawei and Chinese surveillance equipment supplier Vikor can send an alert if a crowd starts to form, according to a marketing presentation. The alert can be set for clusters of three, six, 10, 20 or 50 people.

Many of the surveillance solutions co-developed by Huawei have more innocuous purposes, such as ID swipe machines for companies and schools, or safety monitoring systems for industrial production.

But others lay bare the divergent standards between China and Western nations in policing.

Antoine Griezmann, a French soccer player who had promoted Huawei as a brand ambassador since 2017, announced Thursday that he would terminate his partnership with the company following the “Uighur alarm” reports.

“I take this opportunity to invite Huawei to not just deny these accusations,” Griezmann said in an Instagram post to his more than 30 million followers, “but to take concrete actions as quickly as possible to condemn this mass repression, and to use its influence to contribute to the respect of human and women’s rights in society.”

Griezmann, 29, is one of soccer’s most popular players, scoring four goals in the 2018 World Cup tournament as part of France’s victorious national team. He joined the Barcelona soccer team last year in a deal worth roughly $145 million, the fourth-most-expensive soccer transfer in history.

Like fellow soccer champion Lionel Messi, whom Huawei brought on as another sponsor earlier this year, Griezmann has starred in glossy commercials promoting Huawei’s smartphones to a European audience.

The financial terms of Griezmann’s Huawei endorsement have not been disclosed. Through a representative, Griezmann declined further comment.

Huawei told The Post this week that the “Uighur alarm” report was “simply a test” and that the system had not seen real-world application. The 2018 document was signed by representatives from Huawei and the Chinese facial recognition developer Megvii, whose system, officials said, was not designed to target ethnic groups. It was removed from Huawei’s website shortly after IPVM and The Post asked the companies for more details.

In another statement, the company said it was investigating the test and invited Griezmann to meet personally. Huawei also said the test report had been approved by a Huawei subcontractor, which the company called a “mistake.”

A number of Huawei partners’ systems found on the website mention the capability to track individuals’ ethnicity. One system — developed by Huawei and a Chinese government contractor for aerial photography, Beijing Xintiandi Information Technology — is touted as being able to visualize the identifying details of out-of-town visitors to a city on a 3-D map, including their name, gender, ID number, type of residency permit and ethnicity, according to a marketing presentation from the companies found online.

Marketing materials for products co-developed by Huawei with DeepGlint, Bresee and Maiyuesoft also mention ethnicity identification or search features. The three companies did not respond to requests for comment.

Jerome Cohen, a veteran China human rights legal expert, said racial profiling and discrimination are prevalent in China. The country’s government is “engaging in racial profiling on a massive scale,” he said.

Another presentation for a facial recognition system, co-developed by Huawei and the artificial-intelligence start-up SenseTime, said that it could be used to “suppress illegal petitioning.” “Petitioning,” or shangfang in Chinese, is a process by which individuals can seek redress from the central government for wrongs committed by local officials.

Chinese who attempt shangfang are often intercepted and jailed by local officials who don’t want complaints going outward, Cohen said.

SenseTime did not respond to a request to explain what counts as illegal petitioning and how its product could help prevent it. The Huawei spokesperson also did not explain this point, but said: “We have not and will never support the use of technology to discriminate against vulnerable or marginalized groups.”

The Chinese Foreign Ministry did not respond to requests for comment. A ministry spokesperson told CNBC earlier this week that “legal use of facial recognition in public areas in some parts of China is to improve social management” and prevent criminal acts. The spokesperson called the reports on the “Uighur alarm” by IPVM and The Post “purely slander.”

“The measures are not targeting any particular ethnic groups,” the ministry official added, saying they can “strengthen social security, thus [earning] support from people of all ethnic groups.”

Attempts to reach China’s Public Security Ministry for comment by phone and fax Saturday were unsuccessful.

Another one of the products found in Huawei marketing materials is a “voiceprint” recognition system, created by the Chinese tech company iFlytek, that is advertised as being able to compare a voice recording from a phone or app against a database of “tens of millions” of voices, according to a PowerPoint presentation on the system that carries both iFlytek’s and Huawei’s logos.

The United States sanctioned iFlytek after allegations it was using this technology to help the Xinjiang government track Uighurs. Uighurs have anecdotally reported being pulled aside by authorities at checkpoints and ordered to read a paper aloud to have their voice recorded.

Voiceprint recognition technology is also being developed in the West, primarily for consumer applications such as secure banking, though critics have said its further use could lead to broader privacy and surveillance concerns.

The iFlytek system, as with the other partnerships, is advertised as running on Huawei hardware. The “Uighur alert” test report said that system used Huawei cameras, servers, cloud-computing infrastructure and other tools.

Surveillance systems like the voice-recognition product advertise often-unproven technical abilities, and it’s unclear “how much of it is real and how much of it is boasting,” Wang said. “But the ambition is real,” she added, “whether or not the actual practice has reached that point."

Huawei is the world’s second-largest maker of smartphones and a crown jewel of China’s ambitions in telecommunications and artificial intelligence. The company has worked to capture major deals surrounding international development of the 5G network technology that could reshape the Internet.

But it has also found itself at the center of tensions between China and the U.S. government, which has labeled the company a national security threat. Huawei has disputed U.S. allegations that the company conspired to steal trade secrets.

International watchdogs and human rights activists have said such ethnicity-detection systems could be used to track and persecute minorities. China has detained more than a million Uighurs and members of other mostly Muslim minority groups in reeducation camps in the country’s Xinjiang region, according to United Nations estimates.

The Chinese government has denied wrongdoing and said the camps are designed to provide work training and combat extremism, but U.S. national security leaders have cited reports of torture, forced labor and other human rights abuses.