Google Inc unveiled a new online music store on Wednesday, in a move to challenge the dominance of market leaders Apple Inc and Inc.

The new service feature millions of songs from record labels EMI, Sony Music and Universal, but will not have music from Warner Group, the fourth of the major record labels.

Google, which introduced the service at an event at the Mr. Brainwash Studios in Hollywood, California on Wednesday, said consumers in the United States will be able to purchase the music through its Android Market, which offers smartphone apps, electronic books and videos.

To help jumpstart the new music store, Google said it will offer one free song for consumers to download everyday.

Google will also allow consumers to share purchased songs with friends on the Google+ social network. The feature will give users of Google+ a free, full-play of songs purchased by their friends.

Google is playing catch-up to its biggest rivals Apple, and Facebook, who have all to varying degrees integrated music into their core online and mobile products.

Analysts say selling online music is unlikely to provide much of a lift to Google's revenue. But they say Google needs to be in the market to ensure that its mobile efforts based on Android can match offerings from competitors such as Apple and Amazon.

Without a music service, Android devices such as smartphones and tablets may not seem as attractive to consumers looking for a product that offers a seamless media experience.

(Reporting by Lisa Richwine in Los Angeles, Yinka Adegoke in New York and Alexei Oreskovic in San Francisco, editing by Gerald E. McCormick, Bernard Orr)