The US government has launched an official investigation into advanced chips installed in Huawei’s latest smartphone technologies, sparking a debate in Washington over the effectiveness of sanctions aimed at curbing a geopolitical rival.

The US Commerce Department has imposed a series of sanctions against Huawei and the Chinese chipmaker over the past two years. It is installed inside the Mate 60 Pro phone. ‬

The chips are manufactured by Semiconductor Manufacturing International, a Chinese company that has been blacklisted by the US. Huawei—it has restricted access to US technology. ‬

Chinese tech giant Huawei Technologies has added a first-class handset to its controversial “Mate 60” lineup of smartphones, Bloomberg reported earlier.