Spotify is changing the way its mobile applications work and introducing a free music streaming option. Smartphone and tablet users previously needed to subscribe to a Premium account to play tracks through their devices, but the service has added the same system it employs for its desktop apps to mobile.

The new service is ad-supported and comes as a result of successful negotiations with major record labels, including Sony, Warner and Universal. It will allow those without a paid subscription to stream songs to their phones. Playlists and radio-style offerings will be the mainstay of the new service. If you tune into your favourite artist for example, you will get their tracks shuffled and randomly played to your device. You will have the option to skip them, but not select chosen tracks individually.

READ: Spotify reportedly adding free, ad-supported listening to mobile apps

The announcement came during a press conference in New York hosted by Spotify's founder and CEO, Daniel Ek. It effectively draws battle lines in an ongoing fight with iTunes and the new iTunes Radio service offered by Apple.

Spotify has also recently revealed that it is to add merchandising links to artists' pages in order to help big and smaller bands and singers to make money on the side. There will be no charge to the artist for this service.

"Spotify is making it easier than ever for artists to get their music on Spotify, and to get discovered, and now with these tools to get fans to shows and drive additional revenue. It's amazing for artists and it's an awesome experience for fans," Pocket-lint was told by Mark Williamson, director of artist services at the time. 

Speaking of artists, Led Zeppelin's music has been added to Spotify.

Specifically, Led Zeppelin I and Led Zeppelin II are available now, while the rest of Zeppelin's discography will arrive sometime this week. This marks the first time Led Zeppelin's music catalogue can be streamed on demand. According to The New York Times, Led Zeppelin and its management team have been in negotiations with streaming services since January.

READ: Spotify has paid out over $1 billion to artists, half of that in 2013 alone

Lastly, as part of the announcements today, Spotify revealed it has added 20 new markets, mostly throughout South and Central America. The new markets include: Bolivia, Bulgaria, Chile, Colombia, Costa Rica, Cyprus, Czech, Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Hungary, Malta, Nicaragua, Panama, Paraguay, Peru, Slovakia and Uruguay.

Spotify's CEO also noted that users in 2013 have streamed 4.5 billion hours of music, and they'e created 1.5 million new playlists every day. Spotify didn't mention how many users it now has, but the service had over 6 million subscription users and more than 24 million active users as of March 2013.