A group of music publishing companies said Monday it is joining a copyright infringement lawsuit against Google Inc.'s video-sharing site YouTube.

The National Music Publishers' Association said it was joining the lawsuit out of concern that many songwriters weren't receiving proper compensation when their music appeared on YouTube videos.

The lawsuit also includes as plaintiffs The Football Association Premier League and Viacom Inc., a media company that owns MTV, Paramount Pictures, Nickelodeon and Comedy Central.

The plaintiffs say YouTube is breaking the law by hosting video clips that they hold the copyrights to. However, YouTube says it's complying with the law by immediately taking down any clips found to be violating copyrights after receiving notification.

David Israelite, chief executive of the NMPA, said in a statement that the music publishers' group was "very concerned about YouTube's approach to copyright."

The lawsuits have been combined for trial purposes into one case being heard by U.S. District Judge Louis L. Stanton in New York.

Music publishing companies administer the copyrights of songwriters and composers and collect the royalties that are due to them.