Toyota Motor Corp. unveiled the new Prius, its leading hybrid car, in Las Vegas on Tuesday, saying it will be 10 percent more fuel-efficient than existing comparable vehicles.

The fourth-generation Prius comes at a time when driver interest in the United States is shifting toward larger, less fuel-efficient vehicles due largely to low gasoline prices. The redesigned Prius will also likely be challenged by increasing competition from makers of electric vehicles such as Tesla Motors Inc.

The new Prius, with its first restyling since 2009, will be marketed in Japan toward the end of this year, Toyota said, and in the United States from early next year.