The Trump administration’s decision to halt all foreign use of Anthropic’s most-capable AI models was prompted by conversations between Amazon.com Chief Executive Andy Jassy and U.S. officials including Treasury Secretary Scott Bessent, people familiar with the matter said.

Researchers at Amazon had used a series of prompts to get Anthropic’s Fable 5 model to provide them with information that could be used to aid cyberattacks and was supposed to be off-limits, Jassy told the officials, according to people familiar with the matter. Tech industry executives have been in regular touch with the administration about the power of cutting-edge AI tools.