The global auto industry remains heavily exposed to the Xinjiang region of China for raw materials, components and other supplies, a new report has found, despite a recent U.S. law intended to restrict purchases from the area, where the Chinese government has committed human rights abuses against mostly Muslim minorities.

The report, from a team of researchers led by Laura T. Murphy, a professor of human rights and contemporary slavery at Britain’s Sheffield Hallam University, details the links between Chinese companies with deep ties to Xinjiang and the automakers that use their supplies, such as metals, batteries, wiring and wheels.

The report identifies major Chinese companies that the researchers determined have participated in coercive labor programs in Xinjiang, or have recently sourced their materials and products from the region, where China has engaged in mass internment of Uyghurs and other minorities. Those Chinese firms are major participants in the global supply chain for auto parts, the report says, raising the likelihood that automakers like Volkswagen, Honda, Ford Motor, General Motors, Mercedes-Benz Group, Toyota and Tesla have sold cars containing raw materials or components that have at some point touched Xinjiang.

“There was no part of the car we researched that was untainted by Uyghur forced labor,” Dr. Murphy said. “It’s an industrywide problem.”

Such links could pose serious problems for the international auto brands. The Biden administration, like the Trump administration before it, has taken an increasingly aggressive posture toward Chinese trade violations and imports of goods made with forced labor, which the United Nations estimates affects 28 million people worldwide.

Under the Uyghur Forced Labor Prevention Act, products made wholly or partly in Xinjiang are now assumed to have been produced with forced labor, making them vulnerable to seizure by the federal government if they are brought into the United States. Customs officials say that since the law went into effect in June, they have stopped roughly 2,200 shipments — valued at more than $728 million — that were suspected of having Xinjiang content. More than 300 of those products were ultimately released into the United States.

Federal officials did not disclose what kinds of products have been seized. But the new rules have been particularly disruptive for companies making clothing and solar panels, which source raw materials like cotton and polysilicon from Xinjiang.

The New York Times has not independently verified the entire contents of the new report, which names roughly 200 companies, both Chinese and international, with potential direct or indirect links to Xinjiang. Many of the Chinese industrial giants named in the report have multiple production sites, meaning they could be supplying international automakers with metal, electronics or wheels made from their factories outside Xinjiang.

The global supply chain for auto parts is vast and complex. According to estimates by McKinsey and Company, the average automotive manufacturer may have links to as many as 18,000 suppliers in its full supply chain, from raw materials to components.

Many of those suppliers run through China, which has become increasingly vital to the global auto industry and the United States, the destination for about a quarter of the auto parts that China exports annually. Xinjiang is home to a variety of industries, but its ample coal reserves and lax environmental regulations have made it a prominent location for energy-intensive materials processing, like smelting metal, the report says.

Chinese supply chains are complicated and opaque, which can make it difficult to trace certain individual products from Xinjiang to the United States. Over the past three years, Xinjiang and other parts of China have been intermittently locked down to keep the coronavirus at bay. Even before the pandemic, the Chinese government tightly controlled access to Xinjiang, especially for human rights groups and media outlets.

Determining the extent of coercion that any individual Uyghur worker may face in Xinjiang’s mines or factories is also difficult given the region’s restrictions. But the overarching environment of repression in Xinjiang has prompted the U.S. government to presume that any products that have touched the region in their production are made with forced labor unless companies can prove otherwise.

Workers in the region “don’t have a chance to say no,” said Yalkun Uluyol, a Xinjiang native and one of the report’s authors. Goods coming from Xinjiang “are a product of the exploitation of the land, of the resources and of the people,” he said.

The report’s researchers identified numerous documents — including Chinese-language corporate filings, government announcements and ocean import records — indicating that international brands, at the very least, have multiple potential exposures to programs in Xinjiang that the U.S. government now defines as forced labor.

Dr. Murphy said her team had identified nearly 100 Chinese companies mining, processing or manufacturing materials for the automotive industry operating in the Uyghur region, at least 38 of which had publicized their engagement in repressive state-sponsored labor programs through their social media accounts, corporate reports or other channels.

International automakers contacted by The Times did not contradict the report but said they were committed to policing their supply chains against human rights abuses and forced labor.

G.M., Volkswagen and Mercedes said their supplier codes of conduct prohibited forced labor. Honda said its suppliers were required to follow global sustainability guidelines. Ford said it maintained processes to ensure that its global operations, including in China, complied with all relevant laws and regulations.

Toyota, in a statement, said, “We expect our business partners and suppliers to follow our lead to respect and not infringe upon human rights.”

Tesla did not respond to repeated requests for comment.

The Chinese government has insisted that there are no human rights violations in Xinjiang, and has called accusations of forced labor in Xinjiang “the lie of the century.”

“‘Forced labor’ in Xinjiang is a lie deliberately made up and spread by the U.S. to shut China out of the global supply and industrial chains,” Liu Pengyu, the spokesman at the Chinese Embassy in Washington, said in a statement.

Some of the Chinese companies named in the report are enormous industry suppliers that have proudly advertised their role in carrying out the Chinese government’s policies toward Uyghurs in social media postings, or in glossy annual reports.

They include China Baowu Steel Group, the world’s largest steel maker, which has a subsidiary in Xinjiang that accounts for at least 9 percent of its total steel production, according to the report. Baowu and its subsidiaries make springs for car suspension systems, axles and body panels, as well as various kinds of steel that feed the supply chains of most international carmakers.

In its 2020 corporate social responsibility report, which pledges adherence to China’s leader and the Communist Party, Baowu Group said that its subsidiary had “fully implemented the party’s ethnic policy” and that 364 laborers from poor families from villages in southern Xinjiang had “been arranged with employment.” Human rights advocates say the terms are euphemisms for organized mass transfers of Uyghur laborers into factories.

According to the report, Baowu Group subsidiaries have participated in other transfers of workers from poor regions of Xinjiang, and in so-called poverty alleviation programs, which the United States now recognizes as a guise for forced labor. Under the new law, companies that participate in such programs can be added to a blacklist that blocks the products they make anywhere — even outside Xinjiang — from coming to the United States.

The new report also builds on a June investigation published by The Times into Xinjiang’s role in producing electric vehicle battery minerals like lithium and nickel, as well as previous research by a firm called Horizon Advisory into the aluminum industry in Xinjiang. The report identifies recent transfers of Uyghur laborers at some of the world’s biggest aluminum companies, and traces these products to major auto industry suppliers, some of whom made shipments to the United States, Canada or Europe as recently as November, shipping records show.

It also documents ties to Xinjiang and transfers of Uyghur workers for dozens of other significant auto industry suppliers, such as Double Coin, a tire maker that sells widely in the United States, including online at Walmart and Amazon.

And it documents a recent investment by CATL — a Chinese firm that produces roughly a third of the world’s electric vehicle batteries and supplies Tesla, Ford, G.M., Volkswagen and other brands — in a major new lithium processing company in Xinjiang.

Zhang Yizhi, a spokesman for CATL, said the company was a minority shareholder in the Xinjiang company and was not involved in its operations or management. CATL is committed to building a responsible supply chain and strictly opposes and prohibits any form of forced labor in its suppliers, he said.

Baowu Group, Double Coin and its parent, Shanghai Huayi Group, did not respond to repeated requests for comment. Amazon declined to comment about its sale of Double Coin tires, while Walmart did not respond.

The research suggests that the United States still has far to go in stopping the flow of goods linked to Xinjiang. Customs officials say they are working to enforce a ban on such products, but they are still hiring aggressively and working to build out the department’s capacity to identify and stop these goods.

“We’re still in an upward trajectory,” said AnnMarie R. Highsmith, the executive assistant commissioner of the Office of Trade at Customs and Border Protection, in an interview in October.

“Unfortunately,” she added, “the situation globally is such that we are going to have full employment for a while.”