Apple and Google are reportedly in a standoff with the UK's National Health Service due to its specific plans for mobile contact tracing.

On Friday, the two tech firms announced a joint venture to build out a privacy-protecting and Bluetooth-based development framework that health organizations could use to build apps to track and curb the spread of coronavirus.

As part of its privacy protocols, Apple and Google are requiring health organizations avoid a centralized database of user data. That's something the NHS's digital arm, the NHSX, originally planned to do with its app, The Guardian reported.

The API, as it's designed, is meant to track whether a person has come into contact with someone infected with COVID-19. The decentralization protocol is meant to prevent governments from building a surveillance system to track the movements of people on a wider scale.

But if an app doesn't adhere to Apple and Google mandates, it won't be able to take advantage of the benefits. Instead, it will face severe limitations. Without the Apple and Google API, an app is only able to access Bluetooth when it's actually running in the foreground, requiring an app's display to stay unlocked and on to work properly.

Those measures are meant as a privacy safeguard to protect against apps surreptitiously tracking users without their consent.

Prior to the Apple and Google announcement, the NHSX has been hopeful that smartphone makers would lift those restrictions for contact tracing apps.

It's a similar problem that Singapore's TraceTogether app ran into — its Bluetooth tracking didn't work in the background. Reportedly, only 12% of Singapore's population had downloaded the app, far below the 60% many experts say is required for it to be effective.

For its part, the NHSX denied claims of a "standoff" with the tech giants.