The Biden administration hit dozens of Chinese entities with export restrictions on Thursday, accusing them of aiding in the oppression of China’s Uyghur minority or helping Beijing’s military, further ratcheting up tensions between the world’s top two economies.

Citing their alleged use of biotechnology to support the Chinese military, the Commerce Department added China’s Academy of Military Medical Sciences and its 11 research institutes to a trade blacklist, restricting access to U.S. exports.

It said such aid included “purported brain-control weaponry” without defining the technology further.

The department also added HMN International, formerly Huawei Marine, as well as Jiangsu Hengtong Marine Cable Systems, Jiangsu Hengtong OpticElectric, Shanghai Aoshi Control Technology Co., Ltd., and Zhongtian Technology Submarine Cable to the list for allegedly acquiring, or attempting to acquire, technology from the United States to help modernize the People’s Liberation Army.

The Chinese Embassy in Washington did not respond to a request for comment.

U.N. experts and rights groups estimate that more than a million people, mainly Uyghurs and members of other Muslim minorities, have been detained in recent years in a vast system of camps in China’s far-west region of Xinjiang.

China denies rights abuses in Xinjiang and has pushed back against U.S. “interference” in its affairs, vowing to protect its companies against U.S. sanctions.

The U.S. move on Thursday followed a U.S. investment ban placed last week on Chinese facial recognition company SenseTime, and could worsen already rocky relations between Beijing and Washington.

Commerce Secretary Gina Raimondo said China is choosing to use biotechnologies “to pursue control over its people and its repression of members of ethnic and religious minority groups.”

“We cannot allow U.S. commodities, technologies, and software that support medical science and biotechnical innovation to be diverted toward uses contrary to U.S. national security,” she said in a statement.

The Treasury Department is also expected to announce actions targeting Chinese companies that Washington accuses of using biotechnology and surveillance to abuse human rights, a senior administration official said.

The so-called entity list has become a go-to tool for Washington in the U.S.-China tech feud since the Trump administration. Suppliers to companies that have been placed on the list must seek a special license from the Commerce Department to ship goods to the targeted company. The license requests face a tough standard of review.

Thursday’s moves are likely to inject further mistrust into the already shaky U.S.-China relationship, despite President Joe Biden’s effort in a November virtual meeting with China’s leader Xi Jinping to establish “guardrails” to prevent the two superpowers from sliding toward conflict.

Beijing and Washington have been clashing over broad set of issues, including U.S. criticism of China’s expanding nuclear arsenal and the Biden administration’s decision this month for U.S. government officials to boycott the 2022 Beijing Winter Olympics over rights abuses.

Washington has also accused China of genocide against minority Muslims in Xinjiang.

China’s telecommunications equipment giant Huawei Technologies was added to the entity list in 2019 over national security concerns. HMN Technologies, a submarine cable maker, was added to the list later that year.

It has since been divested from Huawei Technologies Co Ltd but is majority owned by Shanghai-listed Hengtong Optic-Electric Co Ltd.

Washington has become increasingly concerned about security threats posed by the company’s role in building undersea internet cables, which have far greater data capacity than satellites.

Last year, it sent warnings to Pacific Island nations expressing strategic concerns about HMN’s bid to participate in a project to improve communications in the region, Reuters reported.

Beijing has consistently denied any intent to use cable infrastructure for spying.