The euro fell 0.31% against the US dollar at the start of the week, pressured by risk-averse flows into the greenback following heightened Middle East tensions and hawkish remarks from a Federal Reserve official. Fed Governor Christopher Waller's warning reinforced expectations that the US central bank may raise interest rates, boosting US Treasury yields and the dollar. The move came as Iran launched strikes, escalating regional instability and driving investors toward safe-haven assets.