SAN JOSE, Calif. - Apple Inc. gave rival smart phone makers another reason for heartburn Monday, claiming its upcoming iPhone will have a battery life that exceeds the company's previous estimate and the battery life of competing phones.

With the iPhone launch still 11 days away, Apple said the hotly anticipated gadget will last for 8 hours of talk time, 6 hours of Internet use or 7 hours of video playback.

When the company previewed the device in January, it said the rechargeable battery could last 5 hours handling any one of those functions.

Competitors' phones -- such as Palm Inc.'s Treo and Research in Motion Ltd.'s BlackBerry Curve -- tout talk times of about 4 hours. Samsung Electronic Co. claims about 5.5 hours for the BlackJack.

The announcement lifted Apple shares, which have soared more than 40 percent over the past three months in anticipation of the iPhone, which combines the functions of a cell phone, iPod media player, digital organizer and wireless Web device.

After a day of heavy trading, Apple shares climbed 3.8 percent, or $4.59, to close at $125.09.

Shaw Wu, an analyst at American Technology Research who has a "buy" rating on Apple, was skeptical, however. "Our sources have indicated iPhone's active use battery life may be closer to around 4 to 5 hours for heavy use, similar to other smart phones," he noted in a research report Monday.

He also predicted Apple will face complaints over the design of the battery, which can't be easily swapped out by users. It's a convenience that other gadget makers often offer but one that Apple has not, most notably in its iPods, forcing users to send in their devices when the battery wears out.

If Apple's new iPhone battery life claims are true, analysts say the gadget will set a new performance standard for smart phones -- handsets that handle voice and data communications.

The Cupertino-based company also said the iPhone battery can handle 24 hours of music playback and up to 10 days of standby time before requiring a recharge.

"It is amazing," said Richard Doherty, president of The Envisioneering Group, a research company. "I'm not aware of any smart phone that has that amount of talk time without needing a battery the size of a cigarette pack."

Apple did not disclose details of how it achieved the new iPhone specifications. Doherty said that since battery technology has only seen limited improvements recently, Apple likely lengthened battery life by optimizing the iPhone's features and components, such as automatically powering down the display or wireless chips when those features are not in use,

"There has to be very efficient circuitry inside," he said.

Given its past legal battles, Doherty thinks Apple might be treading cautiously this time with its performance claims. Apple reached a settlement with affected consumers in another case over allegations of defective batteries in early iPod models.

In another change, Apple said the iPhone's touch-sensitive screen will be made out of glass instead of plastic, for "superior scratch resistance and clarity." Apple has been criticized and sued for how the screens on its iPod Nanos get scratched easily.

The iPhone will only be sold at stores owned by Apple Inc. and AT&T Inc., which has an exclusive deal to offer cellular service for the device when it goes on sale in the U.S. on June 29. It will also be available at Apple's Web site.

The device will be available in two configurations, $500 for a 4 gigabyte model and $600 for one with 8 gigabytes of storage.