Some 150 websites allegedly selling counterfeit goods including shoes, purses, sunglasses and sports jerseys have been seized, authorities said on Monday, coinciding with the Cyber Monday holiday shopping day.

U.S. authorities in the past few days slapped notices on the seized websites, including www.pumaoutlets.net, www.myjerseyshop.com, www.uggbootsclearanceoutletstores.com, in a bid to thwart sales of the counterfeit goods.

However, authorities say they face difficulties prosecuting the sellers of the fake goods because they are typically overseas, predominantly in China.

Most of the actual counterfeiters and criminals involved are overseas and they're using the Internet as a means to defraud consumers here without actually having to set up shop on U.S. soil, John Morton, head of the U.S. Immigration and Customs Enforcement agency, told reporters.

Authorities made undercover purchases from the websites in question and worked with the companies that own the rights to the trademarks to determine the authenticity of the products.

If the products are determined to be counterfeit, officials obtain warrants from courts to seize the websites. The owner of the domain name can try to contest it in court.

Last year officials seized 82 websites to coincide with Cyber Monday, a term coined for the Monday after the Thanksgiving holiday when people return to work and make online gift purchases on their computers in anticipation of Christmas.

China