Both Apple and Google are facing growing pressure to remove a mobile app that can let Saudi men track and restrict the movements of their wives and daughters.

The app, called Absher, was launched by the Saudi Arabian government back in 2015, and is currently available on both the Apple App Store and on Google Play. With it, Saudi residents can use their smartphones to pay traffic tickets, renew a driver's license and access other government services.

But the same app was also designed to follow Saudi Arabia's controversial guardianship laws, which have been accused of restricting women's rights. Earlier this month, the publication Insider wrote a story on Absher and how the app can let Saudi men specify when and where their wives and daughters are allowed to fly out of the country. It can also send an SMS alert when the woman is using her passport to cross the border or check-in at an airport.

This makes the app particularly effective when it comes to stopping Saudi women from fleeing abusive situations. "At least 1,000 women try to flee Saudi Arabia each year, and experts told Insider the text alerts had enabled many men to catch family members before they make it out," the publication said.

The media exposure of Absher has sparked human rights groups and US Senator Ron Wyden to call on Apple and Google to remove the app from their platforms.

"By permitting the app in your respective stores, your companies are making it easier for Saudi men to control their family members from the convenience of their smartphones and restrict their movement," Wyden said in a letter addressed to the companies on Monday. "This flies in the face of the type of society you both claim to support and defend."

Neither company appears to have been aware of the Absher's app controversial tracking functions. But Apple's CEO Tim Cook told NPR his company is going to investigate. "I haven't heard about it," he said of the app. "But obviously we'll take a look at it if that's the case."

Google is also reportedly examining whether the Absher app is adhering to the company's policies.

This article originally appeared on PCMag.com.