British security agencies have identified "shortcomings" in Chinese phonemaker Huawei's telecoms technology that pose "new risks" to UK networks.
In a government report to the UK's national security adviser Sir Mark Sedwill, technical and supply-chain issues were revealed in Huawei's engineering processes which will affect the security of the British telecoms network.
Huawei has come increasingly under fire over security risks in recent years, most notably in the US and Australia where lawmakers have stepped up efforts to bar its equipment from the country's networks.
Best Buy, the largest retailer in the US of consumer electronics, stopped stocking Huawei products, while Australia is preparing to ban the company from supplying equipment for its planned 5G network, according to Reuters.
The company currently supplies broadband equipment to the UK's largest telecoms provider BT, and mobile networks for Vodafone. In Europe, it acts as a major supplier for Deutsche Telekom and Telefonica.
The report was authored by the Huawei Cyber Security Evaluation Centre (HCSEC), an agency set up by Huawei in response to UK government concerns about possible security threats to national infrastructure, and signed off by the UK's National Cyber Security Centre, formerly part of the country's spy agency GCHQ.
"Identification of shortcomings in Huaweis engineering processes have exposed new risks in the UK telecommunication networks and long-term challenges in mitigation and management," officials said in the report.
"Due to areas of concern exposed through the proper functioning of the mitigation strategy and associated oversight mechanisms, the Oversight Board can provide only limited assurance that all risks to UK national security from Huaweis involvement in the UKs critical networks have been sufficiently mitigated."
A Huawei spokesperson upon the report's public release said: "The Oversight Board has identified some areas for improvement in our engineering processes. We are grateful for this feedback and committed to addressing these issues."
Huawei employs 1,500 people in the UK, and in February pledged to spend a further £3bn in Britain following a high-profile meeting between its chairperson Sun Yafang and Prime Minister Theresa May.