Biden administration officials vowed to fully enforce a new ban on imported goods from China’s Xinjiang region beginning Tuesday, warning of close scrutiny for any companies seeking exceptions for goods ranging from solar panels to tomato products.

“We will not allow goods made with forced labor to enter this country,” and “our timely and strong implementation of this law is proof of our commitment to that,” Homeland Security Department’s Robert Silvers told reporters on a Friday conference call. Yet, he stressed, the agency is “also committed to our mission of facilitating the flow of lawful trade and commerce which is so vital to our economy.”

Under the Uyghur Forced Labor Prevention Act, enacted last December, the US government assumes that anything made even partially in the Chinese manufacturing hub of Xinjiang is produced with forced labor and can’t be imported into the US. Companies can win exemptions if they are able to provide “clear and convincing evidence” the goods are free of forced labor.

The law is meant to help combat alleged repression of Uyghurs and other minorities in the Chinese province of Xinjiang. Beijing has repeatedly denied allegations that minorities are compelled to work against their will.

US Customs and Border Protection officials released a list of dozens of entities using forced labor for priority enforcement. US authorities will also prioritize scrutiny on goods imported into the US by companies related to entities in Xinjiang, where there is a higher likelihood they contain inputs from the region.

Biden administration officials said they also are publishing information for importers on the government’s enforcement strategy, including guidance on how companies can overcome the presumption that goods made in Xinjiang are tainted by forced labor and barred from import. Businesses have been seeking the guidance for months, warning of potential disruptions to supply chains already in upheaval.

Administration officials have stressed that tough enforcement should come as no surprise.

“Our department has been warning for years now about the risks of doing business in Xinjiang province,” said Silvers, under secretary for strategy, policy and plans.

The ports of Los Angeles, New York and Chicago are set to be the most impacted, officials said, though they stressed Customs and Border Protection is prepared to handle the extra workload and is working to ensure fragile supply chains will not be unnecessarily stressed.

“We have a clear message for the trade community,” said Christopher Magnus, commissioner of the federal enforcement agency. “Know your supply chain. The trade community has a responsibility to exercise reasonable care and ensure their supply chains are free of forced labor.”