"We've identified a group of apps that are using a third-party advertising SDK, which uses private APIs to gather private information such as user email addresses and device identifiers and route data to its company server," Apple said in a statement.
The SDK is developed by Youmi, a Chinese mobile advertising provider, it said.
"This is a violation of our security and privacy guidelines. The apps using Youmi's SDK will be removed from the App Store and any new apps submitted to the App Store using this SDK will be rejected.

"We are working closely with developers to help them get updated versions of their apps that are safe for customers and in compliance with our guidelines back in the App Store quickly," the company said.