Apple says it sold more than 1.7 million units of its new iPhone model in the first three days, making it the most successful product launch in the company's history.
The iPhone 4 went on sale Thursday in the US, Britain, France, Germany and Japan. High demand for the model caused shortages and unruly crowds at some stores.
Apple Inc. sold more than 1 million units in the first three days when it launched last year's model, the 3GS.
The iPhone 4 features a sharper screen than the previous model, among other changes.