Three Websites that allegedly sell pirated copies of Android apps have been shut down and seized by U.S. government authorities as part of ongoing efforts to battle online software piracy and counterfeiting around the world.

The seized Web domainsâApplanet.net, Appbucket.net and Snappzmarket.comâall now only display a "seizure banner" from the FBI and the U.S. Department of Justice (DOJ). The banners notify visitors that the domain name has been seized by federal authorities due to copyright-infringement issues, according to an Aug. 21 DOJ statement.

"Cracking down on piracy of copyrighted worksâincluding popular appsâis a top priority of the Criminal Division," said Assistant U.S. Attorney General Breuer in the 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 shutdown of the three Websites is believed to be the first such government action specifically involving Android mobile apps in an online marketplace, said the DOJ. The shutdowns were conducted with the help and coordination of Dutch and French law-enforcement agencies.

A Justice Department spokesman could not be reached for additional comment.

FBI agents downloaded thousands of copies of popular copyrighted mobile device apps from the three sites, which are "suspected of distributing copies of apps without permission from the software developers," according to the DOJ.

The sites sold the pirated apps, and the money for the purchases was not sent to the developers who created them, as required with legitimate mobile app marketplaces.

"In most cases, the servers storing the apps sold by these alternative online markets were being hosted in other countries, and our international law-enforcement partners assisted in obtaining or seizing evidence stored on these servers," according to the Justice Department statement. "Nine search warrants were also executed in six different districts across the country today as part of the operation."

"Criminal copyright laws apply to apps for cell phones and tablets, just as they do to other software, music and writings," said U.S. Attorney Sally Quillian Yates of the Northern District of Georgia, in a statement. "These laws protect and encourage the hard work and ingenuity of software developers entering this growing and important part of our economy. We will continue to seize and shut down Websites that market pirated apps, and to pursue those responsible for criminal charges, if appropriate."

The government has previously taken similar actions against other Websites that allegedly sell pirated or counterfeit software.

In January, the FBI shut down the Website, Megaupload.com, one of the largest file-sharing services on the Internet, on charges that it systematically abetted the widespread piracy of copyrighted music, movies, video and other intellectual property.

In a 72-page indictment in that case, the government charged seven people and two corporations, Megaupload Limited and Vestor Limited, of costing copyright holders more than $500 million in lost revenue from pirated movies and other content. The individuals face a maximum penalty of 20 years in prison on racketeering charges, five years for conspiracy to commit copyright infringement, 20 years on money-laundering charges and five years on related charges.

In December of 2011, a federal judge in Nevada ruled in favor of luxury brand Chanel and allowed the company to have about 600 different Websites shut down for selling counterfeit Chanel products.

This week's criminal case against the Android sites included several federal agencies such as the DOJ's Task Force on Intellectual Property and its Computer Crime and Intellectual Property Section; the Office of International Affairs; the U.S. Attorney's Office for the Northern District of Georgia; the FBI's Atlanta Field Office; and six other U.S. Attorneys' Offices, including the Southern District of Mississippi, the Middle District of Florida, the Western District of Michigan, the Southern District of Indiana, the District of Rhode Island and the Northern District of Texas.