Sprint Nextel Corp on Tuesday unveiled the HTC EVO 4G from HTC Corp, the No. 3 U.S. operator's first cellphone that will support its WiMax high-speed wireless service.

The HTC phone has a 4.3 inch screen, which is designed for video viewing and Web browsing and is 30 percent bigger than the screen of the Apple Inc iPhone, Sprint said.

The device, which runs on Google Inc software, has an 8 megapixel camera for taking photos and video and a second camera on the front for applications like video chat.

Sprint said it would start selling the device this summer and would unveil pricing for the phone and its wireless service closer to the launch date. David Owens, a cellphone executive for Sprint, declined to comment on the device's price but said it would be in the high end of the smartphone range.

The device will support Sprint's CDMA network, as well as the higher speed WiMax network operated by Clearwire Corp, in which Sprint has an ownership stake of roughly 56 percent. Analysts had expected the phone to be called Supersonic, which Sprint said was the code name for the phone.

Sprint is hoping its WiMax service will help it stem years of customer losses, as it is the country's first fourth-generation 4G phone.

Its biggest rival -- Verizon Wireless, a venture of Verizon Communications and Vodafone Group Plc -- is also building a 4G network but does not expect to have 4G phones available until the middle of next year.

This is going to be an iconic handset without question, Owens said in an interview on the sidelines of the CTIA show where the phone was unveiled.

Owens said that while the device was designed for the WiMax network, Sprint also expects customers on its older network to buy the phone.

The phone also has a little kickstand that allows it to be placed at an angle for video viewing.

(Reporting by Sinead Carew and Gabriel Madway; Editing by Gary Hill)