Two complaints will be filed by America against China at the World Trade Organization aimed at stopping what it said is piracy of copyrighted movies, music, software, and books.

U.S. Trade Representative Susan Schwab announced that cases will be filed tomorrow at the Genevabased trade arbiter. One case argues that China sets too high a value on pirated movie or music disks before prosecuting violators. The second objects to Chinese restrictions on the sale of foreign books and movies.

“This is something our industry has been frustrated about for a very long time,” the president of the Motion Picture Association of America, Dan Glickman, said in an interview.

The cases escalate trade tensions between the economic powerhouses. They represent the second time this year America will have gone to the WTO to protest grievances against China, which ran up a record trade surplus of $232.5 billion with America last year. In February, America filed a WTO complaint aimed at what it called illegal subsidies to exporters.

“There is no trade war between China and the United States. We have a strong and growing trade relationship,” Ms. Schwab said at a news conference yesterday. “But it should not surprise anyone that there are frictions.”

The complaints about widespread sale of pirated disks dates back at least a decade with China. In 1996, America was set to levy billions of dollars of sanctions against China before the Chinese agreed at the last minute to new measures to curb the export of pirated recordings and computer software.

China’s copying of movies, music, and software cost companies $2.2 billion in 2006 sales, according to an estimate by lobby groups representing Microsoft Corp., Walt Disney Co., and Vivendi SA. The WTO complaints will be the first by America against China for breaching intellectual property rights in a country where copying has extended to handbags, golf clubs, and even pharmaceuticals.