Smartphone firm OnePlus enters US market

A Chinese smartphone company whose high-end products are little known outside a tech-savvy niche entered the US market on Monday with the backing of two key local allies - chipmaking giant Qualcomm and mobile operator T-Mobile - and no questions from US regulators.

The foray by 5-year-old Shenzhen-based OnePlus comes after US mobile carriers AT&T and Verizon this year backed away from plans to work with China's Huawei on high-end phones in the face of pressure from the US government, which claims Huawei is a security risk.

The United States also briefly banned companies from selling goods to ZTE.