According to four people familiar with the matter, the U.S. is considering restricting the shipment of American chip products to memory chip manufacturers in China.

The move, if approved, would prohibit the shipment of US chip production equipment to factories in China that manufacture advanced NAND chips. NAND chips are critical for storing data in devices such as smartphones and PCs, as well as in data centers.

The proposed action could see U.S. officials ban the export of tools to China used to make NAND chips with more than 128 layers. LAM Research and Applied Materials, both based in Silicon Valley, are the main suppliers of such tools.

Chipmakers that will be affected by the move include South Korean memory chipmaker Samsung Electronics and SK Hynix. Samsung has two large factories in China, while SK Hynix is in the process of buying Intel’s NAND flash memory chip business in China.

While the move marks the first US order to impose export controls to target Chinese production of memory chips without specific military applications, it also aims to protect the only U.S. memory chip manufacturers, such as Western Digital and Micron Technology.

However, the sources made it clear that discussions were still at an early stage and that no proposals for regulations had yet been prepared.

The sources for this piece include an article in Reuters.