UK government agency The National Cyber Security Centre (NCSC) told the country’s telecommunications providers ZTE equipment presented a national security risk, which would be “impossible” to manage if the vendor’s equipment was deployed at scale, Financial Times reported.

In a letter to operators, NCSC technical director Ian Levy cited new laws introduced in China allowing the government to exert greater influence over companies as increasing the risk of using equipment from state-owned vendors.

Levy added the UK’s telecoms infrastructure already contained a large amount of equipment supplied by fellow Chinese vendor Huawei, and said the addition of equipment from a second would “render existing mitigations ineffective”.

Using ZTE equipment, it added, would have a “long term negative effect on the security of the UK.”

The NCSC reportedly also cited a near $1 billion fine ZTE agreed to pay the US in March 2017 after being found to have breached US trade laws on exporting goods to Iran.

UK warnings on national security issues associated with using ZTE equipment echo an ongoing row between Huawei and the US government: ZTE so far appears to have largely avoided a similar battle in the country.