Apple announced a voluntary recall of AC wall plug adapters designed for use primarily in Hong Kong, Singapore and the United Kingdom.

In "very rare cases," affected Apple three-prong wall plug adapters may break and create a risk of electrical shock if touched. Apple says. These wall plug adapters shipped with Mac and certain iOS devices between 2003 and 2010 and were also included in the Apple World Travel Adapter Kit. Apple said it was aware of six incidents worldwide.

The recall does not affect any Apple USB power adapters.

Apple is asking its customers to stop using affected plug adapters. Customers should visit apple.com/support/three-prong-ac-wall-plug-adapter for details about how to exchange them for new adapters.

An affected three-prong plug adapter is white, with no letters on the inside slot where it attaches to the main Apple power adapter.