LOS ANGELES (Reuters) - Lawyers representing a woman calling herself "Jane Doe" on Thursday filed a motion that ultimately seeks to retain her anonymity in an ongoing legal battle between communications providers and the music industry over Internet piracy.

Glenn Peterson and Dan Ballard, lawyers with the Sacramento-based law firm of McDonough, Holland & Allen, said they filed the motion -- the first of its kind -- in federal court in Washington D.C. on behalf of a Verizon Communications VZ.N customer who was asserting her privacy and other constitutional rights.

Peterson said the woman was accused of offering songs for free downloading via an Internet file-sharing network.

In recent months, the Recording Industry Association of America (RIAA) has issued more than 1,000 subpoenas to Internet Service Providers demanding the names and addresses of people who share copyrighted music online with the aim of suing them for copyright infringement.

While researchers have pointed to a dip in illegal song-swapping since the RIAA vowed to sue song swappers, the industry has suffered a backlash from privacy rights groups and Internet users.

"This is more invasive than someone having secret access to the library books you check out or the videos you rent," said Peterson.

But Matt Oppenheim, senior vice president for legal and business affairs at the RIAA, said Jane Doe's lawyers were simply trying to obtain "a free pass to download or upload music" from the court.

The RIAA is a trade organization that represents major record labels like AOL Time Warner's AOL.N Warner Music and Vivendi Universal's EAUG.PA Universal Music Group.

Verizon had tried unsuccessfully to challenge the RIAA from issuing subpoenas related to song-swapping on its communications network, but a court in June compelled it to turn over names. That decision is now under appeal. Meanwhile Verizon said it was complying with the court by turning over names.

"When we get a subpoena, we notify the customers the RIAA is seeking their identity, and we ask them to notify us if they are planning on challenging it," a Verizon spokeswoman said.

She said Jane Doe's lawyers asked Verizon to withhold her name because she was planning on challenging the subpoena.

Sarah Deutsch, vice president and associate general counsel for Verizon, said the company would have faced liability had it turned over the woman's name.

"We informed the recording industry that one of our customers intended to challenge and asked the RIAA to deal with the lawyers directly.

Instead, according to Deutsch, the RIAA went to court recently and filed a motion to compel Verizon to provide the name.

"This is just inconsistent with U.S. law. If someone is issued a subpoena requesting identity, you as a citizen or consumer, have the right to hire an attorney and try to prevent your identity from being turned over," Deutsch said.

"We think this is yet another indication of why this law needs to be fixed," Deutsch said, noting that Verizon on Thursday filed a motion to oppose the RIAA's motion to compel.

But Oppenheim countered that "their arguments have already been addressed by a federal judge -- and they have been rejected. Courts have already ruled that you are not anonymous when you publicly distribute music online."