PayPal co-founder and billionaire investor Peter Thiel warned that bitcoin could be a “Chinese financial weapon” used to dethrone the U.S. dollar’s monetary status.

Speaking with former U.S. Secretary of State Mike Pompeo at a virtual roundtable hosted by the Richard Nixon Foundation Wednesday, Thiel opined that, assuming China is long bitcoin, the cryptocurrency could pose a threat to the U.S. dollar’s reserve currency status. The comments come at a time when fears over China’s assumed control over bitcoin are resurfacing.

“Even though I’m a pro-crypto, pro-bitcoin maximalist person, I do wonder whether if at this point bitcoin should also be thought of in part as a Chinese financial weapon against the U.S. … it threatens fiat money, but it especially threatens the dollar,” Thiel said during the stream.

More than being “pro-bitcoin” and owning the asset himself, Peter Thiel’s foundation was key to the creation of Ethereum when Vitalik Buterin drew a $100,000 grant to begin working on the blockchain.

Thiel, best known now for his investment firm Thiel Ventures, has been an outspoken critic of Silicon Valley since he left the tech industry in 2018, claiming companies like Google and Facebook pose threats to the U.S. given their ties to China, topics he touched on in his talk Wednesday as well.