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 State and Treasury Departments say Chinese cybersecurity vendor Sichuan Juxinhe is behind the hacks into numerous US telecommunications companies.