Huawei faces the risk of being unable to purchase data storage devices from three foreign hardware firms using U.S. technology, as Washington presses governments and companies around the world to give the Chinese tech giant the elbow.

On Tuesday, U.S. Senator Roger Wicker, a ranking member of the Senate Committee on Commerce, Science and Transportation, sent a letter to the CEOs of Toshiba America Electronic Components, Seagate Technology and Western Digital, requesting information regarding their compliance with a 2020 U.S. rule designed to restrict Huawei and its affiliates from accessing foreign-produced hard disk drives made with U.S. software or technology.

In August 2020, the U.S. Department of Commerce issued a final rule aimed at limiting Huawei’s ability to procure items that are the direct products of specified American technology and software, such as hard disk drives.

In the letter, Wicker wrote that he is “engaging in a fact-finding process” about whether leading global suppliers of hard disk drives are complying with that rule.

“It is my understanding that foreign-made products resulting from U.S. technology or software now require a license when there is knowledge that items will be incorporated into, or will be used in the ‘production’ or ‘development’ of, any part, component or equipment produced, purchased, or ordered by Huawei and its affiliates,” the lawmaker wrote.

“We requested a license to ship products to Huawei in September 2020. Our application is still pending,” Western Digital said in a statement to Reuters. Huawei did not immediately respond to requests for comment.

In August last year, the former Trump administration added 38 new Huawei affiliates to its Entity List bringing the total number of blacklisted Huawei affiliates to 152 since first adding the Chinese company in May 2019.

Contact reporter Ding Yi (yiding@caixin.com)

Related: Huawei Crashes Out of Global Top Five Smartphone-Makers