European stocks started the week in the red, with the STOXX 50 down 0.5% and the STOXX 600 slipping 0.1%. The decline came as oil prices resumed their climb after Saudi Arabia shut a major pipeline in response to drone attacks, and a planned meeting between Iran and Gulf states was postponed. Global risk sentiment was further undermined after leading AI firms OpenAI and Anthropic called for a slowdown in development due to mounting safety concerns. In equity moves, ASML Holding fell more than 4% and Infineon dropped 6%, ranking among the worst performers on the STOXX 600, alongside Siemens Energy (-4.3%) and Prysmian (-5%).