The Federal Communications Commission (FCC) on Friday designated five Chinese companies as posing a threat to national security under a 2019 law aimed at protecting US communications networks.

The FCC said the companies included Huawei Technologies Co, ZTE Corp, Hytera Communications Corp, Hangzhou Hikvision Digital Technology Co and Dahua Technology Co.

A 2019 law requires the FCC to identify companies producing telecommunications equipment and services "that have been found to pose an unacceptable risk to US national security."

Acting FCC Chairwoman Jessica Rosenworcel said in a statement: "This list provides meaningful guidance that will ensure that as next-generation networks are built across the country, they do not repeat the mistakes of the past or use equipment or services that will pose a threat to US national security or the security and safety of Americans."

The 2019 law used criteria from a defense authorization bill that previously identified the five Chinese companies. In August 2020, the US government issued regulations barring agencies from buying goods or services from any of the five Chinese companies.

In 2019, the United States placed Huawei, Hikvision and other firms on its economic blacklist.

Last year, the FCC designated Huawei and ZTE as a national security threat to communications networks - a declaration barring US firms from tapping an $8.3 billion government fund to purchase equipment from the companies.

In February, Huawei challenged the declaration in a petition filed with the Fifth US Circuit Court of Appeals. Huawei declined to comment on Friday on the new FCC designation. The other four companies did not comment or could not be reached for comment.

The FCC in December finalized rules requiring carriers with ZTE or Huawei equipment to "rip and replace" that equipment. It created a reimbursement program for that effort, and US lawmakers in December approved $1.9 billion to fund the program.