Apple has sold nine million of its new iPhone models in three days. The company said demand for the iPhone 5S has outstripped supply.
The 5S has a fingerprint sensor built into the phone's main button. The cheaper 5C model comes with a plastic back in a choice of colours.
''While we've sold out of our initial supply of iPhone 5S, stores continue to receive new iPhone shipments regularly,'' said chief executive Tim Cook in a statement issued on Monday.
"We appreciate everyone's patience and are working hard to build enough new iPhones for everyone."
The BBC reports Apple shares rose almost 6% on the news before falling back to trade 4% higher.