Unidentified governments are surveilling smartphone users by tracking push notifications that move through Google’s and Apple’s servers, a US senator warned on Wednesday (via Reuters).

In a letter to the Department of Justice, Senator Ron Wyden said foreign officials were demanding the data from the tech giants to track smartphones. The traffic flowing from apps that send push notifications put the companies “in a unique position to facilitate government surveillance of how users are using particular apps,” Wyden said. He asked the Department of Justice to “repeal or modify any policies” that hindered public discussions of push notification spying.

In a statement given to Reuters, Apple said that Wyden’s letter gave them the opening they needed to share more details with the public about how governments monitored push notifications.

For more details, read the full story at MacRumors.