The Trump administration’s decision to halt all foreign use of Anthropic’s most-capable AI models was prompted by conversations between Amazon.com AMZN -1.23%decrease; down pointing triangle 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.