Google unveiled its new Nexus One smartphone Tuesday in a direct challenge to heavyweight Apple's iPhone handsets.
The touch-screen device was billed by Google as a "superphone" and the next step in the evolution of its Android software.
The Internet giant worked with Taiwanese electronics titan HTC to make the Nexus One.
"I think you will see it pushes the limits of what's possible on a smart phone," HTC chief executive Peter Chou said as the smartphone debuted at Google headquarters in Mountain View, California.
"It is very thin and feels good in your hand," he added.
Nexus One handsets are no thicker than pencils and no heavier than keychain Swiss Army knives, Google engineer Erick Tseng said while demonstrating one of the smartphones.
"It is a great marriage of form and function," Tseng said. "It is really light."
Nexus One smartphones are built on the same Android 2.1 software that runs Droid smartphones that recently hit the market but feature innovations including 3D graphics, according to Tseng.
The handsets feature new speech command capabilities that allow users to speak emails, text messages, or Internet search queries.
Nexus One devices can provide turn-by-turn spoken driving directions from a Google mapping program.
Google also launched its own online store at google.com/phone at which the Nexus One will be sold.
Nexus One smartphones will be sold at the Google-hosted Web store for 529 dollars (US) "unlocked," without ties to a telecom carrier.
Nexus One handsets will be offered at prices starting at 179 dollars (US) if paired with T-Mobile service contracts in the United States.
Google has made "strategic partnerships" with telecom firm Verizon in the United States and Vodafone in Europe.
Nexus One devices linked to service from Verizon in the US and Vodafone in Europe should be available by mid-year, according to Google.
Google said it will ship Nexus One devices to buyers in the Singapore, Hong Kong, Britain, and the United States.
Nexus One smartphones are designed to work with a variety of telecom carrier networks.
"You can take out your SIM card from any provider and put it in the phone," said Google vice president of product management Mario Queiroz.
The Internet search and advertising giant has already gained a foothold in the market with its Android mobile operating system, featured in more than 20 phones since starting with T-Mobile's G1 in October 2008.
Nexus One represents a significant departure in that Google is selling the Google-branded phone directly to consumers who will not be tied to any one telecom carrier.
Apple's popular iPhone, for example, is available exclusively in the United States through AT&T.
Analysts have expressed concern that Google's move could irk partners backing handsets based on the Internet firm's open-source Android software.
"I don't see it as a threat," said Sanjay Jha, chief of mobile devices at handset titan Motorola, which recently brought to market a Droid smartphone based on Android software.
"I think the Nexus One is a good phone. I think we will upgrade Droid to the software available on Nexus One."
Chou and Jha took part in the Google press conference, saying they supported the Internet firm's new phone and Web store as a "healthy" expansion of the mobile phone ecosystem.
Google executives sidestepped questions about whether the Nexus One is intended as an "iPhone killer," but did say that it should prove to be a powerful competitor.
Like iPhones, Nexus One devices feature "accelerometer" capabilities allowing images or games on handsets to be controlled with twists or turns.
"The message isn't to the iPhone specifically, it is to consumers," said Google vice president of engineering Andy Rubin. "Choice is a good thing."
Google has an online Android Marketplace stocked with about 20,000 fun, functional or hip applications for smartphones running the software.
Apple's online App Store with a far greater stockpile of applications has been cited as among the reasons iPhones have become globally coveted devices.
Apple on Tuesday announced that more than three billion mini-applications for iPhone and iPod Touch devices have been downloaded from the App Store.
"Three billion applications downloaded in less than 18 months; this is like nothing we've ever seen before," Apple chief executive Steve Jobs said in a release.
"We see no signs of the competition catching up any time soon."Reuse content