Staunch crypto critic Sen. Elizabeth Warren (D-MA) has claimed that crypto mining operations in the U.S. represent a threat to national security, with "foreign adversaries" running crypto mining outfits that could be used "to spy on U.S. military operations."

At a hearing of the Senate Committee on Banking, Housing, and Urban Affairs on Thursday, Warren posed questions to the Assistant Secretary for Investment Security, Department of the Treasury, Paul Rosen, on the threat posed by foreign-owned crypto miners on U.S. soil.

In the hearing, Warren claimed that "one third of crypto mining facilities in the U.S. are owned by citizens of the People's Republic of China, including people with direct ties to the Chinese government," seemingly citing a March 2024 report by Inca Digital.

In response to Warren's query about President Biden's May 2024 order to shut down a Chinese-owned crypto mining operation located near a U.S. military base, Rosen expressed a "generalized concern" that "sophisticated equipment in proximity to sensitive facilities" could be used to spy on those facilities.

Warren added that "foreign-owned crypto mines also threaten the energy grid," arguing that their connection to the U.S. energy grid could leave the U.S. vulnerable to "targeted blackouts and cyber attacks."

She also put forth that foreign nationals have used cryptocurrency to "buy up crypto mines in the United States in secret" and  redoubled her call that stricter anti-money laundering rules be applied to crypto. She noted that using crypto, a Chinese investor was "able to secretly buy a $6 million crypto mine in Texas," adding that crypto mining operations based in the U.S. have used crypto to "secretly send millions of dollars back to China."

Her intense scrutiny of crypto mining in the U.S. comes as she faces headwinds in her campaign to impose tighter restrictions on crypto in the U.S.

Just this week, Sen. Roger Marshall (R-KS) pulled his support for Warren's Digital Asset Anti-Money Laundering Act of 2023. His withdrawal was especially notable because he co-sponsored the bill.

Crypto firms have stepped up their efforts to unseat Warren, who has linked the digital asset class to crimes including child sexual exploitation, terrorist financing and the fentanyl trade.

This month, Ripple Labs donated $1 million to the Commonwealth Unity Fund, a a super PAC set up to support the campaign of one of Warren’s Republican challengers, crypto attorney John Deaton.

In February, it was revealed that pro-crypto super PAC Fairshake, which has raised hundreds of millions of dollars from crypto firms, poured $10 million into attack ads directed at prominent Warren ally Katie Porter, a Democratic congresswoman currently in a four-way race for California’s open U.S. Senate seat.

Edited by Stacy Elliott.