China's President Xi Jinping has broken a six-week silence about the war in Iran, vowing to take a "constructive" role in efforts to end the conflict. Beijing is wary of being drawn into a war it took no part in, and faces a delicate balancing act between its long-term partnership with Iran and its strategic interests in the Middle East and beyond. Yuka Royer speaks with Ja Ian Chong, a political scientist at the National University of Singapore, about what's behind Beijing's calculations.