US Senator Bernie Sanders has told the chief executives of OpenAI, Anthropic, and Meta to 'stand by' their own public promises on artificial intelligence safety, warning that Congress will step in if they do not pause development voluntarily. In a letter dated 10 August addressed to Sam Altman, Dario Amodei, and Mark Zuckerberg, the Vermont independent said their companies were 'racing ahead' with AI systems that 'nobody can fully understand, predict or control'. Sanders built his letter around commitments the companies made themselves, citing Anthropic's 2023 pledge to pause scaling or delay deployment when safety procedures are outstripped, Meta's 2025 statement to stop development if a frontier AI reaches a critical risk threshold, and OpenAI's similar pledge to halt development at a 'critical' threshold. 'That moment is here,' Sanders wrote. The senator pointed to recent incidents, including AI being 'used for the first time ever to create new viruses' and an OpenAI model allegedly 'hacked into another company's computers', claims not independently verified. He quoted Yoshua Bengio and referenced CIA Director William J. Burns comparing AI models to 'digital nuclear weapons'. Sanders closed with an ultimatum: 'If you do not take appropriate action now, my colleagues and I in the U.S. Senate will.'