Apple is offering to replace the faulty chargers
IPhone 3G owners could be at risk of electric shock from faulty power adapters, Apple has warned.
The metal prongs on many of the ultra-compact USB adapters sold with the 3G iPhone model could break off, putting owners at risk.
Apple has urged owners to swap the adapters that came with the phone to minimise risk. No-one has been injured by the faulty adapters as yet.
At risk are iPhone owners in the US, Japan, Canada and Mexico.
Apple said iPhone 3G adapters sold in a further 10 Latin American nations were also faulty.
In a statement Apple said it had found that, under certain circumstances, the thin metal prongs on the power adapter could break off and get stuck in a power socket.
The ultra-compact adapters were sold with every iPhone 3G since the device went on sale in 22 countries on 11 July.
Since the iPhone launched in June 2007 Apple has sold more than six million of the devices. It is not clear how many iPhone 3G handsets have been sold and how many people are at risk.
Apple said it will replace adapters free of charge and that the fixed versions should be available on 10 October. Until then it said owners should recharge their phone by connecting the device to a computer via a USB port.
Replacement chargers can be ordered via Apple's website or at an Apple store from starting on 10 October.