Chinese telecommunications company Huawei allegedly helped North Korea build and maintain its commercial wireless network.

Citing internal documents and conversations with people familiar with the matter, The Washington Post reported on Monday that Huawei has secretly assisted North Korea over the past eight years with telecommunications development.

The report said that Huawei partnered with Panda International Information Technology, a Chinese state-owned firm, in the process. 

The U.S. blacklisted Huawei in May as a national security threat, preventing American companies from selling their equipment to the tech giant without special approval.

The Post said that the revelations raise questions about whether Huawei, which has used American technology in its components, violated U.S. export controls to furnish equipment to North Korea.