US national security adviser Robert O'Brien stated the US had evidence since 2009 that Huawei maintained backdoor access capabilities in its telecommunications equipment. A secret 2010 Dutch report revealed Huawei had unrestricted access to KPN's phone network including customer data. The UK banned Huawei from 5G networks in July 2020. The US shared classified evidence with allies. However, German and British lab tests of Huawei hardware found no confirmed malicious backdoors, making this one of the most contested claims in tech geopolitics.