AT&T Inc. (T) said on Thursday it has hired 2,000 temporary store workers to handle its much-hyped introduction of the iPhone, the first cell phone from iPod music player maker Apple Inc. (AAPL)

The biggest U.S. wireless service provider by customer numbers will be the country's only carrier to offer the device when it goes on sale June 29.

AT&T and Apple said they plan to start selling the device starting at 6 p.m. local time in cities across the country.

AT&T spokesman Mark Siegel said the company hired the extra summer staff for its 1,800 stores in anticipation of "significant demand" for the device.

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AT&T's wireless division employs a total of about 58,000 people.

The iPhone was first announced in January and combines a music and video player with a Web browser and a touch-sensitive screen in place of a keyboard.

AT&T sales staff have received a total of 100,000 hours of training to sell the device, at "the high end of the normal range" with an average of 6 hours per employee, said Siegel.

Apple, which plans to start selling the phone in all of its 162 retail stores on June 29, did not disclose any plans around training or staffing for the launch.

Apple will also start selling the phone online on the launch date, but AT&T will first launch only in its stores.

"This is such an important product we want to make sure people are fully informed," when they buy it, said Siegel.

AT&T stores will close locally at 4.30 p.m. on that Friday to prepare for the launch, then reopen at 6 p.m. until 10 p.m. that night, according to Siegel.

"We want to free people from the rush of what they would normally encounter on a busy day," he said.

AT&T, which is requiring iPhone shoppers to sign up for a 2-year contract, has not yet revealed the service fees it will charge iPhone customers.

The price of an iPhone will be either $500 and $600, depending on the storage space in the phone.

Apple shares rose 1.7 percent to $123.57 in early afternoon trading on Nasdaq. AT&T was 12 cents higher to $39.65 on the New York Stock Exchange.