Wireless operators in Asia have begun to drop Huawei mobile phones after the US put the Chinese telecom-gear giant on a blacklist blocking it from buying vital American components.

NTT Docomo, Japan's largest operator, said on Wednesday it stopped taking pre-orders for Huawei's new P30 handset, while its rival KDDI said it would indefinitely delay introduction of the phone, without elaborating. SoftBank's YMobile announced a similar move, saying it is looking into concerns over the availability of software updates. Taiwanese carrier Chunghwa Telecom said it won't procure new Huawei models.

The moves are a fresh blow for Huawei, the company that's been accused by the US of aiding China in espionage. A supply ban imposed by the Trump administration threatens to cut off Huawei from crucial US software and semiconductors it needs to make its products. The restrictions also spill over to the Android operating system, hitting the manufacturer that recently surpassed Apple as the world's second-largest maker of smartphones.

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A Huawei representative declined to comment. Docomo, KDDI and YMobile didn't say whether they would halt service or sales of all Huawei products.

Flex, a US-based supplier, said on Wednesday that it has stopped shipments to the Shenzhen-based manufacturer until further notice. "We continue to take this situation very seriously," it said in its statement, adding Flex will ensure it remains in compliance with US and other applicable trade laws.

As for smartphones, the most urgent concern among users of Huawei handsets is related to Android, the most popular mobile operating system, a product of Google. A spokesperson for the Mountain View, California-based company said the technology giant will continue to provide software updates and security patches to existing Huawei models for the next 90 days.

"While we are complying with all US government requirements, services like Google Play and security from Google Play Protect will keep functioning on your existing Huawei device," Google's Android unit wrote.

Some owners of Huawei phones around the world took to social media to express concern about whether the cut-off of suppliers would affect their handsets.

Assuring customers

Huawei's marketing team used social media on Tuesday assure customers their phones would continue to be safe and usable.

"Huawei will continue to provide security updates and after sales services to all existing Huawei and Honor smartphone and tablet products covering those which have been sold or still in stock globally," the company wrote to fans in Nigeria.

In Japan, SoftBank is looking into how customers would be affected by the introduction of a Huawei handset, including whether the Android software it runs on will be updated, Maiko Tsuji, a spokesperson for the company, said by phone.

Taipei-based carrier Chunghwa Telecom said it will continue to sell products it offers from Huawei, despite its halt in procurement, according to the statement Wednesday.