LONDON - U.S. Secretary of State Mike Pompeo has warned that the United States will only pass information across what he termed "trusted networks" and criticized close ally Britain over its decision to allow the Chinese firm Huawei to build parts of the country's 5G mobile network.

Speaking to reporters Wednesday en route to London, where he is due to meet Prime Minister Boris Johnson and Foreign Secretary Dominic Raab, Pompeo said putting Huawei into the British system "creates a real risk."

The top U.S. diplomat described Huawei as an extension of China's communist party that is obligated to hand over information to the party, adding that the Trump administration will evaluate Britain's decision.

U.S. Secretary of State Mike Pompeo speaks to reporters aboard his plane en route to London, Jan. 29, 2020.

"We will make sure that when American information passes across a network, we are confident that that network is a trusted one. We'll work with the United Kingdom. We were urging them to make a decision that was different than the one they made and we'll have a conversation about how to proceed," Pompeo said.

Britain had been agonizing over whether to allow Huawei to be part of its 5G rollout, twice postponing the decision since July last year. In the end, the government said it would allow the Chinese firm restricted access to a 35 percent market share of the periphery of the network, rather than the core elements.

Johnson told lawmakers Wednesday the decision offered the best of both worlds.

Britain's Prime Minister Boris Johnson leaves 10 Downing Street to attend the weekly session of Prime Ministers Questions in Parliament in London, Jan. 29, 2020.

"I think it is absolutely vital that people in this country do have access to the best technology available. But that we also do absolutely nothing to imperil our relationship with the United States, to do anything to compromise our critical national security infrastructure," Johnson said at the weekly Prime Minister's Questions in Parliament.

The announcement comes just days before Britain is set to formally leave the European Union on Jan. 31. Some lawmakers fear the Huawei decision could compromise the transatlantic relationship just as Britain seeks to build on its links beyond Europe after Brexit, with a group of Conservative MPs threatening to vote against the government's 5G plans.

"Certainly, U.S. politicians have made some bold threats over the last couple of weeks, but I think this storm will blow over," said James Sullivan, head of cybersecurity at the London-based Royal United Services Institute. "From the UK's perspective, this has been a risk-management decision based on technical assessments."

However, in Washington, Democratic U.S. Senator Mark Warner says there is bipartisan agreement that Britain has made the wrong choice.

FILE - Sen. Mark Warner, D-Va., talks to reporters on Capitol Hill in Washington, Jan. 28, 2020.

"Huawei has been and will continue to be a national security threat," Warner said. "The Brits are our strongest allies. We've got to find a way to work through this. I do recognize as well that in Huawei we've got an equipment vendor that while as a national security threat is also a lot cheaper than any of the other Western alternatives."

Those Western alternatives are lagging behind, notes cyber industry expert Mark Skilton of Britain's Warwick Business School.

"The issue just in a nutshell is whether you want to continue the economic growth 5G can create because of the speed and power of it, versus the national interests of the U.S., particularly over the Chinese dominating the market," Skilton said. "5G networks promise to transform our lives through the so-called 'internet of things.' Everything from domestic refrigerators to critical national infrastructure will be connected through near-instantaneous networks. That presents many more 'attack points.'

"There is a threat of potentially embedding 'Trojans' or malware into these devices," he added. "Now, if Huawei is the choice of hardware, then they could embed — and I'm not saying they are, but they could — embed this kind of surveillance technology or stealth technology."

The European Union on Wednesday adopted similar guidelines to Britain, stopping short of banning Huawei but imposing strict security rules.

For its part, Huawei welcomed the British decision Wednesday and insisted it does not "take orders" from the Chinese government.

