The Shanghai Composite Index opened lower by 23.15 points, or 0.60%, to 3,853.63 points today, tracking Asian stock markets pressured by surging oil prices amid escalating tensions in the Middle East. Brent crude futures closed above $100 a barrel for the first time since May, after Iran-backed Houthi rebels in Yemen attacked two Saudi oil tankers in the Red Sea, intensifying global supply disruptions.