U.S. authorities have shut down a number of websites in the latest crackdown on online trafficking in counterfeit goods.

More than 130 domain names were seized by US authorities over the weekend in an operation described as “the largest yet,” according to the website Torrent Freak.

U.S. Immigration and Customs Enforcement (ICE) spokeswoman Gillian Christensen declined to specify the number of domain names seized, but told AFP “these seizures are a part of an ongoing law enforcement operation.”

“No further details are available at this time,” Christensen said.

Torrent Freak published a list of 131 domain names which it said had been seized in the past 24 hours.

Visitors to the seized domains were confronted by US government web-placards reading, “This domain name has been seized by ICE — Homeland Security Investigations, pursuant to a seizure warrant issued by a United States District Court.”

The placard informs visitors that copyright infringement is a federal crime, carrying a penalty of five years in prison and a $250,000 fine, while trafficking in counterfeit goods carries a 10-year sentence and a $2 million dollar fine.

The seizure of the websites, part of a campaign known as “Operation In Our Sites,” comes just a few days ahead of the busiest online shopping day of the year in the United States, often called Cyber Monday.

Last November, U.S. authorities shut down 82 websites selling mostly Chinese-made counterfeit goods. That crackdown led numerous prominent download sites to migrate their server operations to foreign countries – such as Montenegro – that do not have the stringent anti-piracy laws the U.S. does.

American authorities are seeking more legislation, hoping to gain even more tools to crack down on websites accused of content piracy and the sale of counterfeit goods.

Pending bills in the US Congress and Senate have received the backing of the Motion Picture Association of America, the Recording Industry Association of America, the US Chamber of Commerce and others.

But they have also come under fire from digital rights groups and Internet giants such as Facebook, Google, Twitter and Yahoo! who say the laws pander to corporate interests, raise serious censorship concerns, and threaten the very architecture of the Web.