The Treasury Department has announced sanctions in connection with a massive Chinese hack of American telecommunications companies and a breach of its own computer network.

The U.S. Treasury Department on Friday imposed sanctions on alleged hacker Yin Kecheng and cybersecurity company Sichuan Juxinhe Network Technology Co., accusing both of being involved in a series of hacks against American telecom companies.

The U.S. Treasury Department said Sichuan Juxinhe Network Technology Co. was directly involved in the deep compromises of the telecommunications firms.