US Secretary of State Mike Pompeo has said his country will help the UK reduce risks associated with involving Huawei in its 5G network.
He said officials would work together to “get this right” after the UK’s decision to give the Chinese firm a limited role in building its system.
Mr Pompeo added that intelligence-sharing arrangements between the two countries would continue.
The US has long argued that Huawei’s equipment poses a spying risk.
But the UK government gave the green light to Huawei’s involvement in 5G on Tuesday, despite previous pressure from the US to block the firm.
The company will, however, be banned from supplying kit to “sensitive parts” of the network, known as the core.
Speaking at the Policy Exchange think-tank in London, Mr Pompeo said his country considered that using the firm’s technology was “very difficult to mitigate” and was “not worth the candle”.
But he said US allies, including the UK, had to make their own “sovereign decision” about whether to involve the company.
Mr Pompeo said: “The Chinese Communist Party presents the central threat of our times.”
He told the audience that Huawei was “deeply tied” to the party, and countries would be taking a risk in involving it in the construction of telecoms networks.
But he added: “I am very confident that our two nations will find a way to work together to resolve this difference.”
Mr Pompeo had previously suggested Huawei’s equipment posed a spying risk, saying that “we won’t be able to share information” with nations that put it into their “critical information systems”.
Huawei will only be allowed to account for 35% of the kit in a network’s periphery, and will be excluded from areas near military bases and nuclear sites.
The company has always denied that it would help the Chinese government attack one of its clients.
Its founder has said he would “shut the company down” rather than assist “any spying activities”.
Speaking alongside Mr Pompeo, Foreign Secretary Dominic Raab said the UK had taken a “targeted approach” towards involving the company.
He said the dominance of the Chinese company in the telecoms sector was the result of a “market failure” for which the government needed to take some responsibility.