President Donald Trump has declared a national emergency over "threats against information and communications technology and services in the United States".
In a statement, the White House said the move is designed "to protect America from foreign adversaries who are actively and increasingly creating and exploiting vulnerabilities in information and communications technology infrastructure and services in the United States".
It is expected to precede a ban on US firms from using foreign telecoms that pose national security risks.
While the order does not name any company, many believe it will impact Chinese tech giant Huawei as trade tensions between the two nations escalate.

Saudi Arabia intercepts 3 missiles, 3 drones targeting different regions
White House press secretary Zacharia fired in less than a week after facing criticism
Indian police detain 'cockroach' movement founder Dipke ahead of protest
Pope Leo to make Sunday appearance after 'steady improvement'
Thousands march in Albanian capital as anti-government protests spread