WASHINGTON (Reuters) -Medical monitoring technology company Masimo sued U.S. Customs and Border Protection on Wednesday over a decision by the agency that allowed Apple to import Apple Watches with blood-oxygen reading technology during a patent dispute between the companies.

Masimo said in the lawsuit in Washington, D.C., federal court that Customs improperly determined that Apple can import watches with pulse oximetry technology, reversing its own decision from last year without notifying Masimo.

Masimo told the court that it learned of the agency's August 1 decision only after Apple announced it would reintroduce blood-oxygen reading to its watches last week.

Spokespeople for Apple and Customs did not immediately respond to requests for comment. A Masimo spokesperson declined to comment.

Irvine, California-based Masimo has accused Apple of hiring away its employees and stealing its pulse oximetry technology to use in its Apple Watches. Masimo has separately sued Apple for patent infringement and trade secret theft in ongoing federal court cases.

Masimo convinced the U.S. International Trade Commission to block imports of Apple's Series 9 and Ultra 2 smartwatches in 2023 based on a determination that Apple's technology for reading blood oxygen levels infringed Masimo's patents.

Apple has continued to sell Customs-approved redesigned watches without pulse oximetry since the ITC's decision.

Apple said on Aug. 14 that it would reintroduce its smartwatches' blood-oxygen reading capabilities with approval from Customs. Masimo said the agency's decision to approve the watches without input from Masimo or any "meaningful justification" deprived the company of its rights.

"CBP's function is to enforce ITC exclusion orders, not to create loopholes that render them ineffective," Masimo said.

Masimo asked the Washington court to halt the agency's ruling and continue to block Apple from selling watches with the blood-oxygen feature.