United States federal agencies conducted raids on Cyber Monday, shutting down Web sites they said were selling counterfeit goods and copyrighted works.

The Justice Department announced on Monday that it had seized 150 Web sites investigators say were hawking branded goods with illegally altered names. The authorities said their operations were timed to coincide with Cyber Monday.

According to U.S. laws, if a product purchased from a Web site is deemed counterfeit, a federal court can issue a warrant for agents to seize the domain name. The Web site's owner can then dispute the charge in court.

The seizures were conducted under the patronage of Operation In Our Sites, a combined effort by the Department of Justice, the Immigration and Customs Enforcement's Homeland Security Investigations department, the National Intellectual Property Rights Coordination Center and the FBI's Washington field office.

Authorities further said they made the seizures after federal law enforcement agents successfully purchased products, including DVDs, footwear and golf clubs, from retailers they suspected of dealing in counterfeit goods.

Through this operation we are aggressively targeting those who are selling counterfeit goods for their own personal gain, said U.S. Attorney General Eric Holder.

The authorities conducted similar raids last year and seized 82 Web sites in the run up to Cyber Monday.