The Bush administration asked a world trade panel on Monday to force China to crack down on pirated goods, like U.S. movies and software.

Over the past several years, China has taken tangible steps to improve (intellectual property rights) protection and enforcement. However, we still see important gaps that need to be addressed, Sean Spicer, spokesman for U.S. Trade Representative Susan Schwab, said in a statement.

The Bush administration's request for a formal case at the WTO's Dispute Settlement Body comes four months after it launched its challenge. The United States argues that slipshod rules have helped the booming industry of pirated American goods. The black market for these goods costs U.S. companies billions of dollars annually.

U.S. officials want to see more aggressive prosecution in China of those who pirate copyrighted or trademarked materials, and more stringent rules for what happens to pirated material once it's seized.

The two countries held talks in June on the issue, but were not able to resolve their differences.

The complaint is not the only challenge the United States has filed against China.

The Bush administration also is considering requesting a WTO panel on another intellectual property rights issue, while two other cases are moving ahead at the WTO.

We will pursue this legal dispute in the WTO and will continue to work with China bilaterally on other important (intellectual property rights) issues, Spicer said.