All Apple phones so far have had 3.5-inch screens, but the iPhone 5 has a 4-inch display, Apple CEO Tim Cook said at a launch event in San Francisco, according to .

That might be a response to the popularity of phones with bigger screens sold by Samsung, and it provides more real estate for apps and games. It also allows Apple to add an extra row of application icons on each page.

Despite the bigger screen, Apple said its new phone is its thinnest and lightest yet. It weighs 22 grams -- 20 percent lighter than the iPhone 4S -- and is 7.6 millimeters thick, or 18 percent thinner, it said.

It comes in black or white and the prices are the same as for the 4S -- US$199 for the 16GB model, $299 for 32GB and $399 for 64GB, when bought with a two-year carrier contract. The phone can be ordered from Friday and will ship a week later in the U.S., U.K., Japan and other countries, Apple said

The iPhone 5 gets a speedy new chip, the A6, which marketing chief Phil Schiller said doubles the speed of both CPU and graphics operations over the A5. Operations like launching apps and viewing attachments will be twice as fast, he said.