US Secretary of State Mike Pompeo is flying into Britain for talks amid American concern at the decision to allow Chinese tech giant Huawei to have a role in the UK’s 5G network.
Mr Pompeo previously said Huawei equipment posed a spying risk, adding the US “won’t be able to share information” with nations that used it.
But Foreign Secretary Dominic Raab has denied the decision will affect the UK-US intelligence-sharing relationship.
The two men will meet for talks later.
The US State Department said Mr Pompeo’s visit was an opportunity to “reaffirm the special relationship following the UK’s departure from the EU and discuss ways to broaden and deepen trade ties”.
But the case of Harry Dunn is also expected to be discussed, after Washington refused the UK’s request for the extradition of Anne Sacoolas – an American diplomat’s wife suspected of causing his death by dangerous driving.
Mr Pompeo will also meet Prime Minister Boris Johnson during his visit, before flying on to Ukraine on Thursday.
Ahead of Tuesday’s National Security Council decision on Huawei, the US had warned that giving the firm a role in 5G could allow the Chinese government a “back door” into the telecoms network through which they could carry out espionage or cyber attacks.
But the UK said the firm will be barred from sensitive locations, such as nuclear sites and military bases and its share of the market will be capped at 35%.
A Trump administration official said the US was “disappointed” with the decision.
Mr Pompeo urged the UK to prioritise its own and its allies security interests when dealing with Huawei during his last visit to the UK in May.
The UK’s decision also faced a criticism from some senior Conservative MPs.
Tom Tugendhat, former chair of the Foreign Affairs Select Committee, tweeted that the government’s “statement leaves many concerns and does not close the UK’s networks to a frequently malign international actor”.
But UK Defence Secretary, Ben Wallace, downplayed such concerns, telling the BBC the UK should not be “paranoid” that the decision would lead to “Big Brother from China watching us”.
Asked about how the US might react Mr Wallace said: “I don’t know how they’ll react… they’ve made their concerns clear.
“We understand that – we respect that, we’ve given them lots of assurances that the intelligence they share and how they share it.”