The Qatari index .QSI was down 0.2%, with Commercial Bank COMB.QA shedding 1.1%. Sept 12, (Reuters) - Middle Eastern stock markets ended lower on Sunday in response to Friday's decline on Wall street, with the Saudi index hardest hit in the region. The U.S. main stock indexes fell on Friday after data showing persistent U.S. inflation dampened optimism about an easing in U.S.-China tensions after a call between President Joe Biden and China's Xi Jinping.