Industry groups representing China's musicians have filed a lawsuit against the country's Web search leader, Baidu.com, accusing it of copyright violation. The move signaled that domestic artists as well as international firms are disgruntled at the firm's free music search service.

Baidu, whose search engine allows users to listen to and search for song files for free, is taking advantage of China's relatively unsophisticated music industry to boost its advertising income, Music Copyright Society of China and digital music distributor R2G said in a statement.

The firms had filed a suit in Beijing in January, and are calling for Baidu to immediately halt copyright violations and offer compensation.

Earlier this month, Universal Music, Sony BMG Music Entertainment Ltd and Warner Music Hong Kong Ltd have asked a court to order Baidu to remove all links on its music delivery service to tracks that they own the rights to, the International Federation of the Phonographic Industry said.