United States President Donald Trump pressured United Kingdom Prime Minister Boris Johnson and other leaders to join the US in a boycott of Chinese telecommunications company Huawei at Wednesday's NATO summit in London.

Trump labelled Huawei a "danger" and a "security risk", and called on US allies to block the company from participating in 5G network upgrades.

The UK has been reviewing restrictions on Huawei for much of this year, though the Conservative Party leadership contest and the issue of trying to arrange Britain's exit from the European Union have both delayed the final verdict, which is now expected after the UK general election on Dec 12.

"On Huawei and 5G, I don't want this country to be unnecessarily hostile to investment from overseas," Johnson said at the summit, held just outside London. On the other hand, we cannot prejudice our vital national security. Nor can we prejudice our ability to cooperate with other vital Five Eyes security partners－and that will be the key criteria that informs our decision about Huawei."

The US has lobbied fellow members of the so-called Five Eyes intelligence sharing community－Australia, Canada, New Zealand, the US and the UK－to block Huawei from securing 5G contracts.

Both Australia and New Zealand have placed restrictions on Huawei, while Canada is yet to rule on the matter.

On Wednesday, Trump claimed that Italy no longer intends to work with Huawei on 5G.

"I spoke to Italy; they look like they are not going to go forward with that. We spoke to other countries and they are not going to go forward," Trump said. When asked about Trump's comments, Italian Prime Minister Giuseppe Conte said: "We did not address this issue", according to Italian wire service ANSA.

Elsewhere in Europe, France has indicated it will allow networks to continue working with Huawei, while Germany's Parliament is scheduled to debate a potential ban.

At a NATO news briefing last month, French President Emmanuel Macron said he was not looking to stigmatize any particular operator or country when it comes to 5G upgrades.

Last week, German Chancellor Angela Merkel suggested that Germany and France should align future policy on 5G security, which could then serve as a framework for a common solution for the rest of the EU.

On Nov 22, EU member states endorsed new telecommunications regulations, including tougher vetting of 5G suppliers, news that pleased the company.

"Huawei welcomes and encourages the facts-based approach of the EU telecom ministers towards the security of 5G networks," said a spokesperson. "Indeed, this is the model that both German Chancellor Angela Merkel and French President Emmanuel Macron have endorsed as the gold standard for 5G verification.

"Europe can－and must－be a leader, not a follower on the road to a digital future. We are at a crossroads of geo-political contests. 5G has the capability to help tackle many of the challenges ahead－and with Europe in the driving seat, 5G will certainly be a force for good."