The Federal Communications Commission is investigating several Chinese telecom companies, including Huawei and China Telecom, over concerns that some of them are ignoring restrictions on their operations in the US.

The regulator said it had opened a “sweeping investigation” into Chinese groups that also include ZTE, a big telecoms equipment provider, and Hikvision, the world’s largest maker of surveillance cameras. It is also targeting China Mobile International USA, and the US subsidiaries of China Telecom, and China Unicom.

FCC chair Brendan Carr said the agency believed some groups were ignoring previous US efforts to address security threats from China. The FCC has previously revoked some authorisations to operate in the US, and placed some companies on the “covered list” of groups from which the government cannot buy products because they are thought to pose a security threat.