The recording industry sued 477 more computer users April 28, including dozens of college students at schools in 11 states, accusing them of illegally sharing music across the internet.

The Recording Industry Association of America (RIAA), the trade group for the largest labels, praised efforts by colleges and universities to use technology and school policies to crack down on music piracy on their own. But it said the most egregious offenders on campus deserved to be sued.

"There is also a complementary need for enforcement by copyright owners against the serious offenders to remind people that this activity is illegal," said the group's president, Cary Sherman.

The recording industry filed its latest complaints against "John Doe" defendants, identifying them only by their numeric internet protocol addresses. It said lawyers will work through the courts to request subpoenas against the universities and some commercial internet providers to learn the defendants' names.

Campus officials at Mansfield University in Pennsylvania warned students months ago about requests from the recording industry to crack down on copyright infringement on its computer networks.

It threatened to unplug the internet connection for each student identified by the recording industry as illegally sharing music, until the student removed all software used to distribute songs online.

"Not everyone agrees that downloading and file-sharing is copyright infringement," wrote the school's technology director, Connie L. Beckman. "While this may be debatable, Mansfield University is required to comply with the law."

The latest filings brings the number of lawsuits filed by the recording industry to 2,454 since last summer. None of the cases has yet gone to trial, and 437 people so far have agreed to pay financial penalties of about $3,000 each as settlements.

The trade group said the newest lawsuits targeted students at Mansfield; Brown University in Providence, Rhode Island; Emory University in Atlanta; Georgia Institute of Technology; Gonzaga University of Spokane, Wash.; Michigan State University; Princeton University in New Jersey; Sacred Heart University of Fairfield, Conn.; Texas A&M University; Trinity College of Hartford, Conn.; Trinity University of San Antonio; the University of Kansas; University of Minnesota; and Virginia Polytechnic Institute.

Students at 21 additional universities were sued in March. A federal judge ruled that the University of Arizona had to turn over the names and contact information of four students identified in the lawsuits.

Some universities have begun taking creative steps to curtail the music file-swapping craze. In January, Penn State became the first school in the nation to offer students free digital music from the newly relaunched Napster service. The basic service, which is paid for by Penn State, provides music for listening and limited downloading. However, if students want to keep a song or burn it to a CD, they must pay 99 cents per song.