Apple says it will appeal after sales of its newest smart watches were halted in the US over a patent row.

It comes after the White House declined to overturn a ban on sales and imports of the Series 9 and Ultra 2 watches which came into effect this week.

The US International Trade Commission took the action to protect device maker Masimo, which accuses Apple of poaching its staff and technology.

Apple said it "strongly disagrees" with the ruling.

Earlier this month, Apple "pre-emptively" removed the devices from its US site and from stores in the country. Sales elsewhere have not been affected.

The US International Trade Commission (USITC) order, issued in October, was subject to a 60-day review by the president, who has the power to veto the decision. That review period ended on Christmas Day.

The office of the United States Trade Representative Ambassador, Katherine Tai, said on Tuesday that it had decided not to reverse the USITC's decision after "careful consultations".

Apple had asked for a stay on the ban until Customs and Border Protection (CBP) could consider whether the redesigned versions of its watches, which do not include the disputed technology, violated Masimo's patents.

CBP is due to make its decision on 12 January, according to an Apple spokesperson.

The USITC found in October that Apple infringed two patents owned by medical device maker Masimo Corporation.

The California-based company had accused Apple of poaching key staff and taking other steps to steal technology it developed to measure oxygen levels in the blood.

Most versions of Apple's smart watches have included the disputed blood oxygen feature since 2020. Its lower cost SE model do not. Previously sold watches will also not be affected by the ban.

Apple also says it has filed an emergency request to the US Court of Appeals to lift the ban.

"We strongly disagree with the USITC decision and resulting exclusion order, and are taking all measures to return Apple Watch Series 9 and Apple Watch Ultra 2 to customers in the US as soon as possible," the tech giant said in a statement on Tuesday.

Masimo said the White House's decision marks a significant moment.

"This is a win for the integrity of the US patent system, and ultimately American consumers, who will benefit from an ecosystem that rewards true innovation," according to company spokesperson.