Apple CEO Tim Cook has said the company will look into an app that can be used to track and limit the travel freedom of women in Saudi Arabia. “I haven’t heard about it,” the CEO said in an interview with NPR. “But obviously we’ll take a look at it if that’s the case.” In addition to accessing government services such as applying for passports or birth certificates, Insider discovered that the Absher app, also available in the Google Play store, allows male Saudi guardians to list “dependents” by name and passport number and then limit their ability to travel.

Apple and Google have been criticised for hosting the Absher app by human rights groups for facilitating human rights abuses. In comments provided to the Washington Post, Amnesty International said that the app highlights the “disturbing system of discrimination” in the country, while a spokesperson from Human Rights Watch joined their call for Apple and Google to investigate the app.

The app highlights a “disturbing system of discrimination”

Democratic Senator Ron Wyden went a step further in an open letter to Tim Cook and Google CEO Sundar Pichai, and called for them to remove the app entirely from their app stores. In the letter, he said:

“I ask that you take immediate action to prevent your technical infrastructure, including your app stores, from being used by the Saudi government to enable the abhorrent surveillance and control of women. Your employees and your customers expect better, as do millions and millions of Americans who support America’s promotion of basic rights and dignity around the world.”

Under Saudi Arabia’s guardianship system, women from the country aren’t allowed to travel without permission from their male guardian, typically a relative. As well as placing limits on their ability to travel, guardianship rules also prevent them from making other major decisions such as getting married, or taking on a job with a private company without the approval of a male guardian.

Absher platforms for individuals and businesses have more than 11 million users, according to the Saudi Interior Ministry website.

Correction: The original quote in this article that was attributed to Senator Ron Wyden was from a Human Rights Watch letter. The article has been updated with the correct quote.