The Recording Industry Association of America (RIAA) has filed suit against XM Satellite Radio, alleging the latter firm is infringing the copyright of music labels by allowing its subscribers to record songs.

US music fans who subscribe to XM Radio and own an Inno recorder from Pioneer can use the device to listen to satellite radio broadcasts, record songs, then replay them as MP3 files.

On Tuesday, the RIAA said XM was committing "massive wholesale infringement" of copyright sound recordings, and asked the court to stop XM's broadcasts and award it damage payments.

By allowing listeners to record MP3 files, XM is acting as a competitor to legal online music stores such as iTunes, Napster and Rhapsody, the RIAA said.

In fact, XM Radio is marketing the Inno as an alternative to the Apple iPod, using the advertising phrase "It's not the pod, it's the mothership."

RIAA members deny they are opposed to satellite radio in general. "We celebrate the growth of XM and Sirius. We think the downloading capability of XM's Inno is attractive and appealing - it just needs to be licensed," the RIAA said in a statement.

A spokesman for XM Radio did not respond to requests for comment for this story.

Listeners in the US have been able to legally record songs off commercial, analogue radio stations for years.

The RIAA says in the case of satellite radio it is different because the broadcast is digital, so XM subscribers can scan through a broadcast and record only certain songs.

"Because XM makes available vast catalogues of music in every genre, subscribers will have little need ever again to buy legitimate copies of plaintiffs' sound recordings," the RIAA said.

In its lawsuit, RIAA says that XM already has the ability to stop the practice. XM currently embeds software code in its encrypted satellite transmissions that deletes saved songs if a user stops paying his XM subscription fee. RIAA says XM could use that same code to prevent users from recording certain songs.

This lawsuit is similar to one that the RIAA brought against XM's rival, Sirius Satellite Radio. In that case, Sirius agreed to make it harder for listeners to record specific songs on its S50, a handheld satellite radio similar in size and price to the Inno.