The US Federal Communications Commission (FCC) initiated a formal proceeding to revoke China Unicom’s operating licence, the regulator’s latest move against Chinese companies due to national securities concerns.

In a statement, the FCC explained China Unicom failed to “dispel serious concerns” about its operations during preliminary questioning conducted in 2020, though noted it will seek fresh input and evidence from the operator, US government agencies and the public as part of a consultation.

During a briefing, acting FCC chairwoman Jessica Rosenworcel explained the process is designed to offer licensees “abundant opportunities to respond to criticisms and explain to us their position” before any action is taken.

She was unable to say how long the process would take.

The FCC took similar action against international termination service provider Pacific Networks and its subsidiary ComNet, which officials previously said are indirectly owned by the Chinese government.

It is also in the process of ditching China Telecom’s operating licence.

The FCC’s campaign began in April 2020, when various Chinese operators were asked to respond to allegations they posed a threat to US national security and demonstrate they were not controlled by their government.

All four companies vehemently denied the accusations and argued the regulator had no grounds to cancel their licences.