On Thursday, Brendan Carr, a Republican commissioner at the Federal Communications Commission, called for United States national security agencies to investigate two Chinese telecommunications providers.

Carr called for the investigation at an FCC Open Meeting on Thursday, prior to voting on a measure that would block a separate Chinese company, China Mobile, from operating within the US. Carr used some of his time at the dais to target China Unicom and China Telecom, two other Chinese telecom companies that are currently operating within US networks, claiming that security threats have changed since these companies were allowed interconnection rights nearly 20 years ago.

“The evidence I’ve seen in this case calls those existing authorizations into question,” Carr said in a statement. “For instance, the decision today cites reports that China Telecom has been hijacking US traffic and redirecting it through China.”

Carr would like to see national security agencies determine if the FCC should revoke the authorizations of these Chinese companies to operate within the country. If revoked, this would require these companies to pull out of the US market. He also asked for the FCC to open a proceeding into the matter.

“It’s time for the US to take additional action,” Carr said. “Security threats have evolved over the many years since those companies were granted interconnection rights to US networks in the early 2000s. Much if not all of the reasoning behind today’s decision appears to apply with equal or greater force to those legacy authorizations. Let’s ensure that our decisions from decades past don’t inadvertently endanger American interests.”

Over the past year, regulators, federal law enforcement, and lawmakers have grown increasingly concerned that incorporating Chinese telecommunications equipment in US networks could pose a national security threat by allowing the Chinese government to peer into the networks.

Democratic commissioner Geoffrey Starks also voiced concern over authorizations given to these other Chinese telecommunications companies, but he didn’t go as far as to call for an investigation. “Earlier commissioners granted [authority] to other carriers with similar ownership structure to that of China Mobile,” Starks said. “The executive branch underscores how the national security environment has changed since they were granted.”

No commissioner other than Carr has called for a similar investigation.

The measure being voted on today to block China Mobile from US networks was approved in a 5-0 vote. Last month, when the measure was announced, FCC chairman Ajit Pai said: “It is clear that China Mobile’s application to provide telecommunications services in our country raises substantial and serious national security and law enforcement risks.”