In a direct challenge to President Donald Trump, Senator Marco Rubio suggested Sunday that Congress would take steps to prevent the Chinese tech firm ZTE from being able to operate in the United States.
Trump had announced last week that he would allow the telecom giant to stay open, in a sharp reversal after the United States had imposed crippling penalties on the company for sanctions violations.
In an appearance on CBS News' Face the Nation, Rubio said there is "a growing commitment in Congress to do something about what China is trying to do to the United States" and that "one of the things that Congress will do is ... not even allow Chinese telecom companies to operate in the United States".
"None of these companies should be operating in this country," he said, also naming the Chinese telecom firm Huawei. "None of them."
Rubio has been a leader of the congressional charge against Trump's plans to ease the restrictions on ZTE that were imposed after it broke US sanctions by selling products to Iran and North Korea.
As part of a deal reached last week with ZTE, the firm would be required to buy American-made parts and pay a US$1.3 billion ($1.9b) fine.
But lawmakers like Rubio remain unconvinced that the terms will do anything to keep China from using companies like ZTE to target US national and corporate security.
"They are used for espionage ... whether it's routers or anything else, they embed stuff in there that could be used to spy against us, not just for national security," Rubio said.
"That's how they steal corporate secrets. That's how they transfer technology. If they can't force you to do it through a business deal, they steal it from you."
The senator did not go into specifics about what kind of legislative measure Congress might pursue to block the President.
The annual defence authorisation bills being considered in Congress already contain a prohibition on the federal government using Huawei and ZTE products.
Rubio has also proposed legislation that would do the same, as well as ban sales of intellectual property and "national security sensitive technology" to China.
But on Sunday, the senator seemed to suggest that Congress should go even further. He guessed that there would be ample support among lawmakers to overcome any potential veto from the President.
"I believe it'll have a supermajority," Rubio said. "I think most members of Congress have come to understand the threat China poses."