Citing unexpected demand in the United States, Apple Inc. on Wednesday announced that it will delay international release of its iPad tablet computer by one month to the end of May.

Apple first rolled out iPad in the U.S. market on April 3 with models that only have Wi-Fi links to the Internet.

The company had originally planned to sell the iPad in other nine countries as well as shipping models with both Wi-Fi and 3G connectivity in the U.S. in late April.

Though over 500,000 iPads were delivered during the first week since the product's debut in the U.S., Apple said demand is far higher than predicted and will likely continue to exceed the company's supply over the next several weeks.

"Faced with this surprisingly strong U.S. demand, we have made the difficult decision to postpone the international launch of iPad by one month, until the end of May," Apple said in a statement.

According to Apple, international customers can begin to take online pre-orders of iPad on May 10 for delivery in late May.

"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 U.S. thus far," Apple noted in the statement.