The U.S. agency responsible for government contracts has released an interim rule for a ban on federal purchases of telecommunications equipment from five Chinese companies, including Huawei and ZTE.

The ban will also negatively impact three more companies including Hikvision, Hytera and Dahua.

The ban is part of a broad U.S. push against Huawei Technologies, the world’s largest telecommunications network gear maker, which Washington accuses of espionage and stealing intellectual property, Reuters reported.

Huawei says it is not controlled by the China government, military or intelligence services. It has filed a lawsuit against the U.S. government over the restrictions in the defense policy bill.

The ban was included in the National Defense Authorization Act (NDAA) passed last year, and restricted the use of federal money to purchase telecommunications equipment and services and video surveillance equipment from covered telecom companies, citing national security concerns.

Huawei said in a statement that it continues to challenge the constitutionality of the ban in federal court.

A spokesman for Hikvision said it is committed to complying with laws and regulations. Hikvision has made efforts to ensure the security of our products adhere to what is mandated by the U.S. government.

Government contractors have said they were confused about the scope of the ban and what it will mean for their businesses.

The first rule implementing the ban was posted on a website for contractors called Acquisition.gov run by the General Services Administration, the government agency responsible for contracting. The interim rule is slated to take effect on Aug. 13.

The government will accept comments on the rule for 60 days before it comes to a final version. It will allow agencies some ability to grant waivers through Aug. 13, 2021, for contractors where security is not at issue.

The ban, which will apply to contracts with any company that uses equipment from the companies, will take effect in August 2020.

In June, the White House Office of Management and Budget had asked Congress for two additional years to phase in the ban – a request that was quickly rebuffed by Republican national security hawks.