Federal authorities announced Monday that they have seized the domain names of 150 websites accused of selling counterfeit or pirated merchandise.
Agents from the Department of Homeland Security and the FBI coordinated the effort for "Cyber Monday," the day that for many shoppers kicks off the online holiday shopping season.
Undercover agents had been buying merchandise from the websites for three months. Then they contacted big companies to make sure the items were phony before taking over the domain names.
Federal authorities said the websites, which sold professional sports jerseys, golf equipment and DVD sets, among other items, will now greet visitors with a seizure banner that notifies them of the government action and informs them that copyright infringement is a federal crime.
The websites tried to lure in unsuspecting shoppers with great deals on what turned out to be phony merchandise, authorities said.
"For most, the holidays represent a season of good will and giving, but for these criminals, it's the season to lure in unsuspecting holiday shoppers," Immigration and Customs Enforcement Director John Morton said in a statement.
"More and more Americans are doing their holiday shopping online, and they may not realize that purchasing counterfeit goods results in American jobs lost, American business profits stolen and American consumers receiving substandard products," he said. "And the ramifications can be even greater because the illicit profits made from these types of illegal ventures often fuel other kinds of organized crime."
The Justice Department has 60 days to notify the owners of the websites about the seizures in case the owners want to challenge the effort in court. But criminal division chief Lanny Breuer said virtually all such takeovers become permanent.
NPR's Carrie Johnson reported from Washington for this story, which contains material from The Associated Press.