LONDON (AP) — Apple said Friday it's delaying its plan to scan U.S. iPhones for images of child sexual abuse, saying it needs more time to refine the system before releasing it.

The company had revealed last month that it was working on a tool to detect known images of child sexual abuse, which would work by scanning files before they're uploaded to iCloud.

"Based on feedback from customers, advocacy groups, researchers, and others, we have decided to take additional time over the coming months to collect input and make improvements before releasing these critically important child safety features," Apple said in an update posted at the top of a company webpage detailing the device-scanning plans.

Apple had said in its initial announcement that the latest changes will roll out this year as part of updates to its operating software for iPhones, Macs and Apple Watches.