Apple today said it has delivered more than 500,000 iPads during its first week. The company says demand is far higher than they predicted and will likely continue to exceed their supply over the next several weeks.

Apple says that it has also taken a large number of pre-orders for iPad 3G models for delivery by the end of April. Faced with this “surprisingly strong US demand,” the company is postponing the international launch of iPad by one month — until the end of May.

Apple will announce international pricing and begin taking online pre-orders on Monday, May 10. “We know that many international customers waiting to buy an iPad will be disappointed by this news, but we hope they will be pleased to learn the reason — the iPad is a runaway success in the US thus far,” the company says in a statement.