The United States will evaluate how it will continue to share important information with governments that have 5G networks using equipment and components from "untrusted vendors", said Mr Robert Strayer, US Deputy Assistant Secretary of State for Cyber and International Communications and Information Policy.

He was referring to Chinese telecommunications equipment maker Huawei, blacklisted by the US on national security concerns.

Mr Strayer was in Singapore to attend the three-day Singapore International Cyber Week (SICW), which ended yesterday, and to meet Asean officials to explore ways to work more closely together to train cyber-security talent to better fob off threats.

At a media roundtable yesterday after SICW, Mr Strayer said: "The nature of 5G - because there could be the exfiltration of data potentially - we will have to do a serious evaluation of how we will continue to share important information with governments, with countries that have 5G networks that have untrusted vendors... It's a very granular kind of assessment that needs to occur."

He was responding to questions on what the US would do if Asean nations were to continue to work with Huawei to build their 5G networks.

Huawei is accused of spying and stealing intellectual property, and is in the crossfire of an escalating trade and technology war between China and the US.

In May, US President Donald Trump put the Chinese telecoms giant on an "entity list", which bans American companies from doing business with the firm without government approval.

The US has been trying to stop its allies from using 5G systems supplied by Huawei for fear that China could use its equipment for espionage. So far, only Australia, Japan and Vietnam have joined the Huawei ban.

Singapore has been encouraging vendor diversity in its telecommunication systems to mitigate risks from dependency on any one vendor.

Asked to comment on this approach, Mr Strayer said: "You can have diversity and exclude untrusted vendors."

He listed alternative vendors such as Ericsson, Nokia and Samsung to address immediate needs for 5G equipment.

But the industry is moving away from hardware to software-based technologies such as radio access networks, which he said will be even more diverse in terms of the number of suppliers.