SAN RAMON (California) • Chevron has asked its global employees to remove Tencent Holdings' WeChat from their work phones, making it one of the first United States companies to heed the Trump administration's executive order banning the Chinese social app over alleged national security risks.

The oil giant identified WeChat as a "non-compliant application", asking those who installed the app on their work handsets to delete it within days or be disconnected from the company's network, according to a staff e-mail viewed by Bloomberg News.

"Due to a recent executive order banning the use of WeChat, Chevron is requiring that you remove the application from your mobile device," said the memo, which also identifies the operating system and model of each employee's phone.

"If no action is taken prior to Sept 27, your access to the Chevron system will be removed."

A company representative declined to comment and a Tencent spokesman did not immediately respond to a request for comment.

WeChat has emerged as a top target in President Donald Trump's campaign against China ahead of the US presidential election in November. Tensions between Washington and Beijing are escalating as his administration wages a campaign that has also ensnared China's ByteDance and its video-sharing app TikTok.

WeChat was supposed to disappear from US app stores last Sunday under Mr Trump's executive order.

But a San Francisco judge issued a preliminary injunction at the weekend to halt the order, saying it is against free-speech rights.

WeChat has 19 million regular users in the US and more than a billion worldwide.

The app is a gateway to many of Tencent's most lucrative businesses, including games and digital payments.

It is also a heavily used marketing and communication tool for American businesses reaching out to their Chinese counterparts or consumer audience.

BLOOMBERG