HONG KONG, - China and Hong Kong stocks weakened on Tuesday, joining a broader retreat in the region, after Beijing kept key lending rates unchanged and stronger GDP data dampened expectations for additional stimulus* China's blue-chip CSI300 Index dropped 0.5% by the lunch break, while the Shanghai Composite Index was 0.1% weaker** Dragging the broader market lower, the CSI Banks Index and the financial sector were both down 1.4%.