Donald Trump has declared a national emergency to protect the US against “foreign adversaries” taking advantage of computer network vulnerabilities.
The president signed an executive order which effectively bars US firms from using foreign telecoms that are believed to pose a security risk to the country.
Mr Trump did not name specific countries or companies as he issued the order but experts suggested it is mainly directed at Chinese telecoms giant Huawei.
The company has long been seen as a front for spying by the Chinese military or security services but it denies these allegations.
Federal Communications Commission Chairman Ajit Pai applauded Mr Trump's executive order, saying it would safeguard the US communications supply chain.
"Given the threats presented by certain foreign companies' equipment and services, this is a significant step toward securing America's networks," he said.
The Trump administration has been trying with only some success to persuade allied nations not to use Huawei equipment. Last year, Trump signed a bill that barred the US government from using equipment from Huawei and China's ZTE Corp.
The US, which is embroiled in an escalating trade war with China, also has sounded warnings about Huawei's efforts to expand into Europe.
Officials are worried that China could use Huawei gear to gain access to private, commercial or other information that could compromise NATO and allied intelligence operations.
Early this year, the Justice Department unsealed criminal charges against Huawei, a top company executive and several subsidiaries, alleging the company stole trade secrets, misled banks about its business and violated US sanctions.
The sweeping indictments accuse the company of using extreme efforts to steal trade secrets from American businesses - including trying to take a piece of a robot from a T-Mobile lab.
The executive charged is Huawei's chief financial officer, Meng Wanzhou, who was arrested in Canada in December. The US is seeking to extradite her.
Agencies contributed to this report
