Apple shares rose nearly 3 percent on Wednesday after it announced sales of more than 600,000 iPhone 4s, a record for just a single day of pre-orders. That put the device on track to surpass sales of its previous iPhone models as well as its iPad tablet computer, and sounded a strong challenge to rivals like Nokia Corp, which warned of weaker-than-expected sales at its phones unit.

But Apple apologized on Wednesday for having to halt sales temporarily after the surprising volume of online interest overloaded order and approval systems and supplies ran out.

Apple's website said Wednesday afternoon that products ordered then would be shipped by July 14, three weeks after the phone's scheduled June 24 launch in stores and slower than the July 2 shipment promised earlier in the day. The site was still slow on Wednesday, making it unclear if orders were going through.

The phone's exclusive U.S. carrier AT&T Inc said it had halted pre-orders and that sales would resume as soon as inventory becomes available.

Full story: Reuters