Asian stocks retreated with Hong Kong's benchmark Hang Seng Index opening down 289 points, or 1.15%, at 24,985. Mainland China's Shanghai Composite Index fell 0.31%, Japan's Nikkei 225 opened 0.57% lower, and South Korea's Kospi was down 0.18%. Brent crude futures rose to $101.40 per barrel, having broken through the psychologically crucial $100 mark on Wednesday for the first time since July, driven by the widening Middle East conflict. Investors are awaiting US producer and consumer price inflation reports due later today and tomorrow, which will influence the Federal Reserve's monetary policy decisions.