The United States is closely watching developments in China after the removal of a top general, Secretary of State Marco Rubio said Wednesday, as he pointed to corruption as the cause. Rumors had swirled about the reasons for the probe before Saturday’s announcement in China, where President Xi Jinping has launched a sweeping drive stated as aiming to root out graft. They’re obviously not sharing with us or talking to us in depth about any of that, but it’s certainly something we watch with interest,” Rubio said. Meanwhile, Washington’s top envoy in Beijing signaled business ties between the world’s two biggest economies are on more solid ground after their trade war truce last October. Ambassador David Perdue reportedly told a closed-door meeting of business leaders in Hong Kong that the US and China had made progress on several agreements.