Senior US officials have reportedly warned it would be "nothing less than madness" for the UK to allow Chinese tech giant Huawei a role in their 5G infrastructure.
The comments come amid reports in the Financial Times that suggest Washington has stepped-up efforts to try and prevent Downing Street from backing the Chinese technology firm's involvement in the 5G network.
In a separate incident, US Secretary of State Mike Pompeo said intelligence-sharing relationships with European allies who use Chinese tech are "potentially at risk".
Speaking at a Silicon Valley Leadership Group, Mr Pompeo said "European countries" are "keenly aware of the need to protect the private information" but added:
"And yet they're prepared to make that, allow that information transit across Chinese infrastructure".
- Secretary of State Mike Pompeo says use of Chinese technology could put intelligence-sharing relationships "at risk":
Mr Pompeo's warning comes just days after the head of MI5 said he had no reason to think Britain’s intelligence-sharing relationship with the US would be damaged if Chinese tech giant Huawei was given access to the UK’s 5G network.
Secretary of State Pompeo told an audience in San Francisco "this is technology that the Chinese Communist Party will have access to," he added:
"Make no mistake about it, they'll have the capacity to get it this deeply personal information."
Senior US officials have also presented the British Government with information to persuade it not to allow the Chinese tech firm to get a lucrative foothold in the UK market.
A decision is due later in January but the Prime Minister has said he would not risk Britain's security when upgrading the nation's 5G network - but said critics of Chinese technology firm Huawei must come up with an "alternative" provider.
In an interview with the BBC on Tuesday, Mr Johnson said he did not want to "prejudice" the country's ability to share intelligence with allies.
Huawei's Vice President Victor Zhang has defended the company, saying in a statement he is "confident that the UK Government will make a decision based upon evidence, as opposed to unsubstantiated allegations."
He added: "Two UK parliamentary committees concluded there is no technical reason to ban us from supplying 5G equipment
"This week the Head of MI5 said, there is ‘no reason to think’ the UK’s intelligence-sharing relationship with the US would be harmed if Britain continued to use Huawei technology."
The statement also said Huawei had "worked with the UK’s telecoms companies for 15 years".
Opposition to the technology has also been expressed in the UK.
Tory MP Bob Seely called for the Foreign Affairs Committee to open an immediate investigation into Huawei’s suitability for use in Britain’s 5G network.
Bob Seely said Huawei "to all intents and purposes is part of the Chinese state" and a deal with the tech giant would allow Beijing to access the UK’s network.
He told MPs during the Queen’s Speech debate that Huawei is "the subject of US investigation for fraud and commercial espionage".
Mr Seely continued: "Huawei, to all intents and purposes, is part of the Chinese state and allowing Huawei a role in the 5G network is effectively to allow China and its agencies access to our network, and to say otherwise is simply false."
Foreign Office minister Andrew Stephenson said a final decision will be "taken in due course", adding: "The Government will consider the full range of risks when making this decision."