NEW YORK (Reuters) - Apple Inc said on Monday it has sold 1 million units of the new iPhone in its initial weekend, on par with estimates set by analysts, sending its stock rising more than 2 percent.

The original iPhone, introduced in late June 2007 in the United States only, sold about 270,000 units in its first two days. Sales had topped 1 million units by early September. The new device sells in 21 countries.

Apple executives were pleased with the early results. "IPhone 3G had a stunning opening weekend," Apple Chief Executive Steve Jobs said in a statement. "It took 74 days to sell the first 1 million original iPhones, so the new iPhone 3G is clearly off to a great start around the world."

Still, iPhone sales pale compared with those of established mobile phone makers, such as Nokia Oy, which sells almost 10 million phones each week, or Samsung Electronics Co Ltd and LG Electronics Inc, which each ship more than 100 million phones a year.

While those phone makers often unveil dozens of models in year, Apple has only one, and its sales spark a retail frenzy as consumers around the world line up to grab one.

The iPhone 3G still has the popular touch screen, but also offers a faster wireless network and the ability to download third-party applications like games.

Perhaps more important, the new iPhone sells for about $200 in the U.S., about one-half the price of its predecessor.

"We don't yet know the breakdown of how many phones were sold to new customers and how many existing iPhone customers upgraded, but regardless, sales during the first weekend were very impressive," said Jeff Kagan, an independent telecommunications analyst, in a note.

Analysts said iPhone sales may dent sales and profit margins at Samsung and LG this year.

Activation problems marred its U.S. launch on Friday, with many buyers leaving stores frustrated that they could not use the hotly anticipated gadget after waiting in line for hours.

AT&T Inc, the sole U.S. carrier for the iPhone, blamed problems synchronizing the phone with Apple's iTunes online music and software store, saying it was probably caused by too many people trying to access iTunes at the same time.

Analysts expect Apple to exceed its original target of 10 million iPhones by the end of 2008.

"The iPhone 3G launch was clearly not as smooth as last year's launch. However, demand was clearly strong across the U.S. ...," said Morgan Keegan analyst Tavis McCourt in a note to investors.

Shares of Apple gained $3.85 to $176.43 on Nasdaq, where it was among the most active issues. The stock, down about 12 percent so far this year, earlier hit a session high of $179.30.

(Reporting by Franklin Paul; Editing by Lisa Von Ahn/Jeffrey Benkoe)

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