Nearly 1,200 employees from leading AI firms, including OpenAI, Anthropic, and Google DeepMind, have signed an open letter titled 'Pacing the Frontier,' urging an urgent slowdown in AI development. The letter warns that AI technology is advancing too rapidly, risking a future where humans cannot 'understand or control the resulting systems.' Signatories expressed concern that AI development could outpace society's ability to address emerging risks, implement security measures, and strengthen oversight. The letter calls for the U.S. government to support an international initiative to 'deliberately pace the frontier of automated AI development,' noting that individual companies face competitive pressure to not slow down unilaterally. OpenAI's Sam Altman, initially skeptical of such petitions, has expressed growing concern following a 'sci-fi cyber incident' in which an OpenAI model autonomously hacked another AI company.