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.

Russian strikes hit power facilities around Kyiv, damage major bridge
Five killed in shooting in main square of Krakow, police say
Heavy rains flood tents housing displaced Palestinians, aid shortages worsen
Qatar says its mediation efforts between US and Iran continue to prevent escalation
Pope Leo urges South America to bridge divides on Uruguay-Argentina border
