Federal authorities have seized the domain names of 150 websites accused of selling counterfeit or pirated merchandise.

The seizures were announced on "Cyber Monday," the day that for many shoppers kicks off the online holiday shopping season. Officials from Immigration and Customs Enforcement, along with the FBI, led the investigation.

ICE officials 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 federal action and informs them that copyright infringement is a federal crime.