Four U.S. agencies yesterday announced a coordinated attack to stem the global trade in counterfeit merchandise and pirated music and movies, an underground industry that law-enforcement officials estimate to be worth $500 billion each year.

The effort, known as the Strategy Targeting Organized Piracy (STOP), includes stepping-up border enforcement to intercept fake goods as they are entering the United States, targeting the earnings of traders of counterfeit goods and publicizing the names of overseas companies that traffic in counterfeit products.

"The message to the . . . pirates and counterfeiters is simple," said U.S. Trade Representative Robert B. Zoellick. "We will do everything we can to make their life miserable." Joining the campaign are the Justice Department, the Commerce Department and the Department of Homeland Security, which includes the customs and border-protection bureau.

At a joint news conference, agency heads said they will employ some of the same tactics against counterfeiters that they have used to identify and track suspected terrorists in the wake of the Sept. 11, 2001, attacks.

These include examining and following likely sources and shipping methods of counterfeiters in advance, and auditing products after they enter the country to ensure that their importers are authorized to distribute them.

The initiative has been in the works for a year, said Commerce Secretary Donald L. Evans, because of the increasing importance of intellectual property to the global economy. The department also is setting up a hotline for small businesses so they can report theft or learn about how to better protect their goods overseas.

Knock-off clothing, electronics, perfume, jewelry and other accessories have for years been part of the urban street landscape around the world. Because of advances in technology that have streamlined manufacturing and distribution, and the growth of the digital music and video industries, counterfeit goods now account for as much as 7 percent of all global trade, according to industry and law-enforcement estimates.

This trend has come despite previous crackdowns by U.S. authorities. As a result, it is difficult to know whether the new measures can stem the tide.

Last year, seizures of counterfeit goods at U.S. borders totaled $94 million, according to the office of U.S. Immigration and Customs Enforcement, an investigative arm of the Department of Homeland Security. In the first half of this year, the number stood at $64 million.

These figures do not include seizures by the FBI and other law-enforcement agencies at warehouses around the country after the goods have slipped through.

Leading the tally of counterfeit goods seized by Homeland Security is cigarettes, followed by digital media such as movies on DVDs, music on CDs and software.

The initiative envisions even closer cooperation with authorities in other countries, increased pressure in trade negotiations for a crackdown on counterfeiting, and making extradition of counterfeiters to the United States easier.