The Federal Communications Commission (FCC) is looking to strip three Chinese telecom firms of their US operating licenses.

China Unicom Americas, Pacific Networks and ComNet had failed to explain their links to Beijing, the FCC said.

The US communications watchdog has long argued those links could pose a national security risk.

The move signals that US president Joe Biden is likely continue Donald Trump's tough approach on Chinese tech firms.

Expelled from US

The FCC voted unanimously on Wednesday to revoke the licenses of the three companies, a move that could see them expelled from the US market.

The companies were asked in April last year to address concerns over the their links to the Chinese government, which the FCC claimed could leave them vulnerable to its "exploitation, influence, and control".

But while the companies have tried to address the FCC's concerns, it has not accepted their explanations.

"The threat to our networks from entities aligned with Communist China is one that we must address head on, and I am pleased that the FCC continues to show the strength and resolve necessary to meet this menace," FCC Commissioner Brendan Carr said in a statement.

China Unicom is a unit of one China's three major telecommunications networks.

Pacific Networks resells international voice and data services to US operators, while its subsidiary ComNet provides a variety of mobile services, including SIM cards and international calling cards.

The FCC granted approvals for the three companies to operate in the US more than a decade ago, when there was less concern in the US about Chinese technology companies.

More scrutiny

Separately, the Commerce Department said it had served subpoenas on multiple Chinese firms which operate in the US, to see if they pose a national security risk.

The move followed a Trump-era executive order, which sought to secure telecommunications and technology supply chain.

The subpoenas will gather information to "allow us to make a determination for possible action that best protects the security of American companies, American workers, and US national security," Commerce Secretary Gina Raimondo said.

"Beijing has engaged in conduct that blunts our technological edge and threatens our alliances," she added.

The department did not name any companies.