Amazon unveiled new models of its Kindle Fire tablet computer on Thursday, including a bigger version with a high-definition display, in a clear challenge to the market-leading iPad.
Analysts said the Amazon upgrades - as well as launching the hugely popular Fire devices outside the US, starting in Europe later this year - signaled the online giant has its sights on challenging Apple's longstanding dominance.
The company unveiled an updated version of its original Kindle Fire 7-inch tablet, with twice the RAM and a faster processor, for $159.
Additionally, Amazon will offer three models in a new Kindle Fire HD line of tablets.
The seven-inch Kindle Fire HD will cost $199 and ships 14 September, while the 8.9-inch version, with 16GB of storage, will cost $299 and go on sale on 20 November.
In an even more direct challenge to the iPad, a 4G version of the 8.9-inch Kindle Fire HD will sell at $499 - the same price as a basic iPad.
"Kindle Fire HD is not only the most advanced hardware, it's also a service," Amazon founder Jeff Bezos told reporters in Santa Monica, California.
"When combined with our enormous content ecosystem, unmatched cross-platform interoperability and standard-setting customer service, we hope people will agree that Kindle Fire HD is the best high-end tablet anywhere, at any price."
Analyst and consultant Rob Enderle tweeted: "Is Amazon the New Apple? I think Amazon just stole the tablet market," adding that for "the key uses of a tablet - reading, games, movies - Amazon is now better in all three."
Industry analyst Jeff Kagan said Kindle Fire "is bigger, stronger and better than before and will compete more directly with the big guys on the playing field."
Bezos said Amazon kept its prices lower than many competitors because it wants to make money from selling content, rather than from devices themselves.
"We want to make money when they use our devices, not when they buy our devices," he told reporters gathered for a press conference, the subject of which had been a mystery before the event.
The Kindle Fire HD announcements came after Bezos unveiled a new Kindle e-reader with so-called "paperwhite" display. It will have a battery life of eight weeks with the backlight on, and will ship 1 October.
The paperwhite Kindle will retail at $119, while a 3G mobile version will cost $179. A new version of the basic Kindle will be reduced in price from $79 to $69.
Amazon, which launched the Kindle Fire in the US market last year, said last week that the first version had captured 22 percent of the market for tablet computers, although it did not reveal detailed sales data.
Offering the Kindle Fire outside the US for the first time, all except the new bigger-screen version will go on sale later this year in five European countries - Britain, France, Germany, Italy and Spain.
"We want to get into as many places as we possibly can over time," Kindle vice president David Limp told AFP.
Apple's iPad has about two thirds of the global market for tablets, and the company is expected to introduce a smaller version later this year.
Limp was cautious when asked if the 8.9-inch Kindle Fire HD was directly aimed at Apple's iPad.
"This is a big market, and I don't want to speak to competitors. But I think they've had a great run in this market, and we're super-excited to join," he said. "Customers in the end will choose how we'll do."