Washington (CNN) -- For the third straight year, federal customs officials marked the Cyber Monday online shopping extravaganza by seizing scores of websites that were allegedly selling counterfeit or falsely labeled products to unsuspecting customers.
For the first time, U.S. authorities said they had partnered with European nations to conduct a similar crackdown overseas.
All told, U.S. Immigration and Customs Enforcement officials said they had seized control of 101 U.S.-based websites, while European authorities had seized 31, with more actions expected.
"The vast majority of these websites are operating overseas and (in) foreign countries in which we are not present. That's part of the challenge here," ICE Director John Morton said. "We're dealing with organized criminals who ... are trying very hard not to be caught."
By partnering with European law enforcement, ICE is bringing transnational pressure to transnational crime, Morton said.
Morton said the websites are growing more sophisticated, mimicking or even duplicating legitimate websites.
The seized websites claimed to be selling familiar name-brand products, including Ergobaby Carriers, New Era hats, Nike sneakers, Tiffany jewelry, Oakley sunglasses, NFL jerseys and Adobe software.
Although some products may have fooled customers, many were inferior products and some should have been obvious frauds. One website sold a DVD entitled "100 Years of Disney," but the Walt Disney Company -- founded in 1923 -- is less than 100 years old, Morton said.
Shoppers who visit the websites will now see a banner reading, in part: "This domain name has been seized by ICE - Homeland Security Investigations pursuant to a seizure warrant issued by a United States District Court."
With the 101 domain names seized this season, ICE's National Intellectual Property Rights Coordination Center has seized 1,630 sites since it began operating in June 2010. Of those, 684 have now been forfeited to the U.S. government, ICE said.
Under the forfeiture process, individuals who have an interest in seized domain names can contest the action in federal court. If no claim is filed, the domain names become the property of the U.S. government.
Morton advised online shoppers to research the websites they use. "Do your homework. Know your supplier," he said. "At the end of the day, trust your instincts. This is probably your best line of defense, so don't reason away your intuition simply for the sake of an extra dollar or two."
ICE officials said that law enforcement agencies from Belgium, Denmark, France, Romania and the United Kingdom, and the European Police Office (Europol) are participating in this year's crackdown, dubbed Project Transatlantic. They executed seizures of foreign-based domains such as .eu, .be, .dk, .fr, .ro and .uk.
The intellectual property center and Europol received leads from various trademark holders regarding the infringing websites. Those leads were disseminated to eight field offices in Baltimore; Buffalo, New York; Denver; El Paso, Texas; Newark, New Jersey; San Antonio, San Diego and Ventura, California, and to the investigating Europol member countries.