Apple's online store was down for maintenance  Thursday night, shortly ahead of starting the preorders for its highly-anticipated iPhone 6 and iPhone 6 Plus.

Apple, the renowned smartphone company, is apparently preparing itself to handle the expected   deluge of pre-orders for the coveted iPhone 6 and iPhone 6 Plus. The online store was taken down Thursday night with a notice indicating maintenance, which is usually associated with a major product launch. The official Apple Store is displaying a "We'll be back" message on its site in different languages.

Apple launched the latest iPhone 6 and iPhone 6 Plus in a special media event on Tuesday and announced the pre-orders for the device starting 12.01 a.m. Pacific time onward on Friday. The first 10 countries that will host the pre-order listing of the new iPhones include the United States, Australia, Canada, France, Germany, Hong Kong, Japan, Puerto Rico, Singapore and the U.K. The shipping of the pre-ordered iPhones will begin after Sept. 19, when the devices are expected to hit the stores.

Apple also set up in-store pickups after placing an order online for the iPhone 6. But given the history of new product launches at Apple, long queues could be an issue, an Apple Insider pointed.

Apple will accept pre-orders from its official website and via Apple Store app. Customers can also buy the device through carriers, including Verizon, Sprint, AT&T and T-Mobile and retailers such as Best Buy, RadioShack, Wal-Mart and Target.

Unlike last year, Apple will make both iPhone models available for pre-orders. The 4.7-inch iPhone 6 with 16GB storage will retail for $199 with a standard two year contract, while the higher end models including 64GB and 128GB will be listed for $299 and $399, respectively.

The 5.5-inch iPhone 6 Plus will be $100 extra with standard contracts, selling at $299 for 16GB storage, $399 for 64GB and $499 for the 128GB model.

Apple is also betting big on its revolutionary iPhone 6 and reportedly planning to sell up to 80 million units by the end of this year, CNET reported.