Amazon's low-cost tablet to come with digital assistant

US online giant Amazon announced Thursday a new small-format tablet that includes its digital assistant Alexa.

The eight-inch (20-centimeter) display Fire HD tablet will start at $89 for US customers, making it one of the least expensive on the market.

"We believe in a different approach to tablets -- providing premium products at non-premium prices -- and customers love it," said Kevin Keith, manager for Fire Tablets.

"In fact, we've seen Fire tablet sales more than double year-over-year as a result. The all-new Fire HD 8 packs more battery life, more storage, faster performance, plus Alexa -- all for less than $90."

Amazon has not release specific sales figures for its tablets. But a survey by research firm IDC estimated the online titan was the fifth largest vendor in the second quarter with global sales of 1.6 million units.

Amazon also sells a seven-inch Fire tablet starting at $49 and a 10-inch device from $230.

The global tablet market, led by Apple's iPad, has been declining over the past few quarters, with some consumers turning to slim PCs, some with detachable keyboards.

Amazon's Alexa, which competes with Apple's Siri, Google Now and Microsoft's Cortana, is a key element of the company's strategy to move into the connected home and internet of things.

Alexa's skills include selecting music, appointment reminders, checking bank balances, ordering food, summoning Uber rides and more.