The U.S. Department of Justice (DOJ) has launched a crackdown on pirated mobile apps with its first seizure of websites accused of selling copyrighted Android apps without permission.

Visitors to the shuttered sites applanet.net, appbucket.net and snappzmarket.com were greeted with a note saying the Federal Bureau of Investigation (FBI) had seized the domain name. The note also warned that piracy is a crime punishable by up to five years in prison and a $250,000 fine.

The three seizures last week were the first time the DOJ has shut down domains for allegedly selling pirated mobile apps. The operation represented the start of a crackdown on illicit app markets.

[See also: Microsoft sues Chinese electronics firms for software piracy]

"Cracking down on piracy of copyrighted works, including popular apps, is a top priority of the Criminal Division," Assistant Attorney General Lanny A. Breuer said in a statement. "Software apps have become an increasingly essential part of our nation's economy and creative culture, and the Criminal Division is committed to working with our law enforcement partners to protect the creators of these apps and other forms of intellectual property from those who seek to steal it."

The FBI worked with authorities in France and the Netherlands, where servers storing the copyrighted apps were located. Law enforcement downloaded thousands of apps from the three sites. The apps would normally be available for a fee on legitimate marketplaces, such as Google Play.

The Justice Department issued nine search warrants, but did not announce any arrests.

The last website shuttered by the FBI was MegaUpload in January. U.S. prosecutors indicted seven people on charges of copyright violations and fraud stemming from the file-sharing site those authorities claimed trafficked in pirated digital content. Four of the defendants are fighting extradition from New Zealand.

Overall, global piracy accounted for a record $63.4 billion in loss revenue to the software industry in 2011, according to the latest report from the Business Software Alliance. The report also found that 57 percent of personal computer users acknowledged acquiring pirated software.

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This story, "Feds Crack Down on Pirated Android Apps" was originally published by CSO .