San Francisco, Sep 23 (IANS): Facebook users have sued its parent company Meta in the US for allegedly tracking them via an in-app browser on iOS devices despite tough Apple privacy policies in place.

The lawsuit, filed in the US District Court for the Northern District of California, alleged that Meta follows users' online activity by "funneling them into the web browser built into Facebook and injecting JavaScript into the sites they visit".

According to a TechCrunch report, that code makes it possible for the company to monitor "every single interaction with external websites".

Apple introduced a major iOS privacy update via iOS 14.5 last year to stop third-party apps like Facebook from tracking user behaviour and their browsing history via App Tracking Transparency (ATT) feature.

However, according to the lawsuit, Meta snooped on users "through a workaround".

The proposed class-action lawsuit "could allow anyone affected to sign on, which in Facebook's case might mean hundreds of millions of US users," the report said late on Thursday.

According to it, Meta is not only violating Apple's policies, but also breaking privacy laws at the state and federal level.

A Meta spokesperson said in a statement that the allegations were "without merit" and it will fight them in the court.

"We have carefully designed our in-app browser to respect users' privacy choices, including how data may be used for ads," the spokesperson was quoted as saying.

Meta Founder and CEO Mark Zuckerberg has admitted that Apple iOS privacy changes will cost the company a whopping $10 billion in 2022.

Meta has also accused Apple of favouring Google over app-based platforms like Facebook with its privacy policies.

"We believe those restrictions from Apple are designed in a way to carve out browsers from the tracking Apple requires for apps. So what that means is that search ads could have access to far more third party data, for measurement and optimisation purposes, than app-based ad platforms like ours," according to Meta.