WASHINGTON: US Secretary of State Mike Pompeo said on Tuesday the United States was not sending "mixed messages" on Huawei Technologies and the Chinese telecommunications giant posed a national security threat to the United States.

"President (Donald) Trump's been unambiguous; I don't think there's a mixed message at all," Pompeo said in an interview with CNBC.

"The threat of having Chinese telecoms systems inside of American networks or inside of networks around the world presents an enormous risk, a national security risk," he said.

The US government blacklisted Huawei in May, alleging the Chinese company is involved in activities contrary to US national security or foreign policy interests.

The United States extended a reprieve that permits Huawei to buy components from US companies to supply existing customers, the Commerce Department said on Monday, but it also moved to add more than 40 of Huawei's units to its economic blacklist.

Trump, however, indicated over the weekend there would be no extension, saying what would happen would be the "opposite." "We're actually open not to doing business with them," Trump said on Sunday.

Huawei, the world's largest telecommunications equipment maker, is still prohibited from buying American parts and components to manufacture new products without additional special licenses.