Larry Page, Google's co-founder and chief executive, speaks during the keynote presentation at Google I/O 2013 in San Francisco.

SAN FRANCISCO - Google Inc. unveiled a streaming music service called All Access that blends songs users have already uploaded to their online libraries with millions of other tracks for a $10 monthly fee.

The service puts the Internet goliath in competition with popular paid subscription plans like Spotify and Rhapsody and free music services like Pandora.

The announcement Wednesday at Google's annual developers conference in San Francisco kicks off a wave of developments in the digital music space that are expected to entice consumers with ways to listen to music on a range of devices.

Rival Apple Inc. is expected to debut a digital radio service later this year; Google-owned YouTube is also working on a paid subscription music plan; and Sweden's Spotify is exploring a way to make a version of its paid streaming plan free with ads on mobile devices, according to a person in the music industry familiar with the matter.

The person was not authorized to speak publicly about the developments because the deals and features on the services have not been finalized.

Google is playing catch-up in the digital music space after launching its music store in November 2011. Apple's iTunes Store, which launched in 2003, is the leader in song downloads and Spotify claims about 6 million paying subscribers worldwide.

But Google's massive reach on mobile devices that use its Android operating system means it could narrow the gap quickly. Some 44 percent of active smartphones in the U.S. are powered by the Android software, according to research firm eMarketer. Google said about 900 million Android devices have been activated worldwide.

All Access will be available in the U.S. on Wednesday and comes with a 30-day free trial. It is expected to roll out soon in 12 other countries were Google currently sells music, including 10 European countries such as the U.K., France and Germany, as well as Australia and New Zealand. If you start the trial by June 30, the monthly fee drops to $8 for the foreseeable future.

Google's All Access allows users to search for songs, albums or artists directly, or peruse 22 different genres. Google curators also offer up recommendations based on your listening behavior and your existing library of songs.

You can listen to any of millions of tracks right away, or switch to a "radio" format that creates a playlist of songs that you might like. Radio playlists can be adjusted on the fly by deleting or re-ordering upcoming songs.

"This is radio without rules," said Chris Yerga, engineering director of Android. "This is as lean-back as you want or as interactive as you want."

By combining an all-you-can-listen-to plan with music sold from its Google Play store, the service covers any gaps. Some artists, like Taylor Swift, keep recent releases off of streaming services for several months in order to boost download sales. The combination also means people can listen to their own specialized music or bootleg recordings alongside the millions of tracks available from Google.

All three major record labels - Vivendi's Universal Music Group, Sony Music Entertainment, and Warner Music Group Corp. - are part of the All Access service.

Listening to music streamed over cellphone networks has become extremely popular. According to research firm eMarketer, over 96 million Americans are expected to stream music on mobile devices at least once a week in 2013, up from 85 million a year ago. About 147 million Americans are expected to stream music on the go at least once a month this year.