New Chinese ambassador to US taking office amid disputes over trade, access to technology, Taiwan

China's new ambassador to the U.S. is taking office amid disputes over trade, access to computer chips and Washington's support for self-governing Taiwan. Chinese state media said Xie Feng arrived in New York on Tuesday and told reporters that relations between the world's two largest economies face "serious difficulties and challenges." Exchanges took a downturn after the Trump administration raised tariffs on key Chinese imports that President Jospeh Biden has maintained, while blocking Chinese companies from accessing the most cutting-edge computer chip technology. China has meanwhile raised its threats to attack Taiwan with regular incursions by ships and fighter jets into airspace and waters near the island that have drawn concerns about a crisis imperiling the global economy.