President Joe Biden on Thursday signed into law a bill banning goods from China’s Xinjiang region unless companies can prove they aren’t made with forced labor, in a move that will add to tensions over Beijing’s treatment of the nation’s Uyghur minority.

The bill passed with unanimous backing in both the House and Senate earlier this month, showcasing how Republicans and Democrats are largely aligned on China policy despite Washington’s deep partisan divisions on most major issues.

The measure is motivated by concern about the oppression of Uyghur Muslims in a region that holds a major place in global supply chains. Xinjiang is a source for cotton used in clothing and is a key location for producing polysilicon used in solar panels, which in turn are seen as crucial in the global shift away from fossil fuels.

The new law could pose a significant challenge for American and other firms that source items from Xinjiang for products used in the U.S. Even before Biden signed the bill, Intel Corp. found itself embroiled in controversy after the chipmaker asked suppliers not to use any labor or products sourced from Xinjiang and then apologized for the move.

The bill requires the U.S. Department of Homeland Security to create a list of entities that collaborate with the Chinese government in the repression of the Uyghurs, a predominately Muslim ethnic minority, as well as other groups. It also contains a “rebuttable presumption” that assumes all goods from the region were made with forced labor unless the commissioner of U.S. Customs and Border Protection gives an exception.

Chinese officials deny that forced labor is used in Xinjiang and call the legislation interference in the nation’s domestic affairs—a line reiterated recently by Foreign Ministry spokesman Zhao Lijian at a regular press briefing in Beijing.

“By fabricating lies and making troubles with such issues, some U.S. politicians are seeking to contain China,” he said. “Their vile scheme will never succeed.”

House Speaker Nancy Pelosi said Congress will continue to condemn and confront the Chinese government’s human rights abuses in Xinjiang, along with locations “from Hong Kong to Tibet to the mainland.”

Bipartisan Backing

“If America does not speak out for human rights in China because of commercial interests, we lose all moral authority to speak out for human rights any place in the world,” Pelosi said in a statement Thursday.

Republican Senator Marco Rubio, one of the bill’s sponsors, said its passage “will fundamentally change our relationship with Beijing.”

“This law should also ensure that Americans no longer unknowingly buy goods made by slaves in China. I look forward to working with the Biden administration and my colleagues to ensure the new law is implemented correctly and enforced properly,” Rubio said in a statement.

Rubio, of Florida, introduced the bill in the Senate along with Senator Jeff Merkley, an Oregon Democrat. It was introduced in the House by Jim McGovern, a Massachusettes Democrat, and Chris Smith, a New Jersey Republican.