Facebook Inc is no longer allowing pre-installation of its apps on Huawei phones, the latest blow for the Chinese tech giant as it struggles to keep its business afloat in the face of a US ban on its purchase of American parts and software.

Customers who already have Huawei phones will still be able to use its apps and receive updates, Facebook told Reuters. But new Huawei phones will no longer be able to have Facebook, WhatsApp and Instagram apps pre-installed.

Smartphone vendors often enter business deals to pre-install popular apps such as Facebook. Apps including Twitter and Booking.com also come pre-installed on Huawei phones in many markets. Twitter Inc declined to comment and Booking Holdings did not respond to a request.

The move by Facebook dampens the sales outlook for Huawei Technologies Co Ltd, whose smartphone business became its biggest revenue generator last year, powered by strong growth in Europe and Asia.

Huawei declined to comment.

Alphabet Inc's Google said earlier that it would no longer provide Android software for Huawei phones after a 90-day reprieve granted by the US government expires in August. But Google's Playstore and all Google apps will still be available for current models of Huawei phones including those which have not yet shipped or even been built.

The Facebook ban, by contrast, applies to any Huawei phone that has not yet left the factory, according to a person familiar with the matter. Facebook declined to comment on when the suspension took place.

In May, Washington banned US companies from supplying technology to Huawei, part of a long-running campaign against the company. The United States alleges that Huawei is too close to the Chinese government and that its telecom network gear and other products could be a conduit for espionage, which Huawei denies.

Buyers of current Huawei phone models that do not have Facebook pre-installed would still be able to download it from the Google Playstore. Future versions of Huawei phones, however, will not have access to the Google Playstore and its apps unless the US government changes course.

Huawei has said it was prepared for the US action and vowed to work around any disruptions. But some customers at stores in Europe and Asia have told Reuters that they are reluctant to buy Huawei phones in the face of uncertainties, and analysts expect a dramatic drop in Huawei smartphone sales.