Gulf stock markets declined as they were rattled by the situation in Iran, with investors awaiting Donald Trump's next move. As investors looked for signs of whether the U.S. might launch new strikes against Iran, most Gulf stock markets traded lower intraday. Saudi Arabia's benchmark index dropped 0.8%, dragged down by a 1.5% fall in Al Rajhi Bank and a 1.3% decline in Saudi National Bank, while Qatar's index narrowed its losses to 0.5%. Iran's Islamic Revolutionary Guard Corps said on Sunday that three oil tankers caught fire after suffering unexplained explosions in the Strait of Hormuz.