SANTA MONICA, Calif. (AP) — Amazon is updating its Kindle Fire tablet computer as it steps up competition with Apple's iPad and refreshing its whole line of Kindle gadgets.

The basic model will cost $159, down from $199 for the old model. It will start shipping Sept. 14. It's also coming with high-end versions, including ones with a screen nearly as big as the iPad.

Amazon also refreshed its line of stand-alone e-readers. Called Paperwhite, the new e-reader model has a black-and-white screen.

The Kindle Fire is an effort to take a larger share of a tablet computer market dominated by Apple's iPad.

Amazon has been selling lower-priced tablets at thin, if any, profit margins to boost sales of digital items from its online store.