The Biden administration has taken its first step to retaliate for China’s broad hack of American telecommunications firms, moving to ban the few remaining operations of China Telecom in the United States.

In a notice issued last week to China Telecom Americas — the U.S. subsidiary of one of China’s largest communications firms — the Commerce Department detailed a preliminary finding that the company’s presence in American networks and its provision of cloud services posed a national security risk to the United States.

It gave the firm 30 days to respond, meaning that the decision on a final ban will almost certainly be up to the Trump administration.

The action was a response to China’s incursion deep into U.S. telecommunications networks, providing Beijing access to data and conversations and giving it insight into spies the United States might be pursuing.

The ban on China Telecom would have more symbolic than financial impact. Even before the latest turn in the cyberconfrontation between the world’s two largest economies, the United States had moved to shrink China Telecom’s presence.

In October 2021, nine months into Mr. Biden’s term, the Federal Communications Commission revoked all licenses for China Telecom Americas to provide ordinary phone services in the United States, saying it was “subject to exploitation, influence and control by the Chinese government.”