European banking regulators issued warnings about advanced artificial intelligence systems, including Anthropic's Mythos, posing a serious threat to financial stability. The European Central Bank's chief supervisor, Claudia Buch, wrote to 110 banks on Tuesday requiring them to submit a plan for tackling cyber risks linked to advanced AI by the end of October. The European Systemic Risk Board cautioned that such technology could threaten financial stability across the eurozone, as it allows criminals to automate sophisticated attacks cheaply, while banks remain slowed by regulation, outdated systems and delayed software updates. The Bank of England issued a similar warning on Tuesday, stating that rapid progress in frontier AI had increased risks to cyber and operational resilience within financial markets. BoE governor Andrew Bailey distanced the UK from the ECB's approach, saying "we are taking a different approach" and "working very closely with the banks." The ESRB raised its assessment of systemic cyber risk from "elevated" to "severe". Anthropic became the first AI company to face export restrictions imposed by the White House, though those restrictions on its flagship models were removed last week after the company agreed to introduce additional safeguards. Bailey called for international cooperation, stating "no single country can think that it can solve that resilience problem on its own."