Donald Trump has stepped up his warning that the US could withdraw intelligence co-operation from countries such as the UK which allow Chinese firm Huawei into their 5G networks.
The US President told one of his ambassadors that “any nation who chooses to use an untrustworthy 5G vendor will jeopardise our ability to share intelligence and information at the highest level”.
The Chinese telecoms firm is regarded as a high-risk vendor by the UK but is being allowed to play a limited role in the country’s 5G infrastructure.
Mr Trump was reportedly furious at the UK’s decision, which came after sustained pressure from Washington on its allies not to use Huawei because of its links to the Beijing government.
The telecoms firm has repeatedly denied claims that it presents a security risk to the West.
With Germany considering its position on Huawei, Mr Trump phoned his ambassador in Berlin from the presidential Air Force One jet to issue a warning about the use of the firm.
Ambassador Richard Grenell said the president “just called me from AF1 and instructed me to make clear that any nation who chooses to use an untrustworthy 5G vendor will jeopardise our ability to share intelligence and information at the highest level”.
In January the UK gave the green light to Huawei to play a restricted part in the 5G network, with Prime Minister Boris Johnson insisting it could be done without jeopardising intelligence co-operation with the US and the other members of the Five Eyes alliance – Canada, Australia and New Zealand.
The Government has acknowledged that Huawei is not a “trusted” supplier but argues that, by banning it from the most sensitive elements of the network and restricting its involvement to 35% on the periphery, it can manage the risk.
Analysis by the National Cyber Security Centre said that if the Chinese state wanted to carry out a major cyber attack there were easier ways to do it than placing “backdoors” in Huawei equipment.