The American Civil Liberties Union and other groups have filed a lawsuit challenging the U.S. Customs and Border Protection (CBP) practice of searching laptops and other electronic devices at U.S. borders.

The lawsuit, filed Tuesday by the ACLU, the New York Civil Liberties Union and the National Association of Criminal Defense Layers (NACDL), challenges a 2008 CBP policy that allows border agents to search electronic devices of any traveler, without suspicion of wrongdoing. In some cases, border agents have copied the contents of the devices or confiscated them. The lawsuit asks the court for an order prohibiting searches of electronic devices at borders without a warrant and probable cause or reasonable suspicion of criminal activity.

The groups filed the lawsuit to "protect the rights of all Americans to cross the border free from intrusive government searches," said Catherine Crump, staff attorney with the ACLU Speech, Privacy and Technology Project.

The border laptop searches violate the Fourth Amendment of the U.S. Constitution, which protects people from unreasonable searches and seizures, the ACLU has alleged. CBP has established a "constitution-free zone at the border," Crump said in a video the ACLU released.

A CBP spokeswoman didn't have an immediate comment on the lawsuit.

The groups filed the lawsuit in U.S. District Court for the Eastern District of New York on behalf of the National Press Photographers Association (NPPA) and Pascal Abidor, a dual French-American citizen who had his laptop searched and confiscated at the Canadian border.

Abidor was travelling from Montreal to New York on an Amtrak train in May when he had his laptop searched and confiscated by CBP officers, the ACLU said. Abidor, an Islamic studies doctoral student, was questioned, handcuffed, taken off the train and kept in a holding cell for several hours before being released without charge, the group said.

When his laptop was returned 11 days later, there was evidence that many of his personal files, including research, photos and chats with his girlfriend, had been searched, the lawsuit alleges.

The incident "made me question how much privacy we actually have," Abidor said.

Documents obtained by the ACLU in response to a separate Freedom of Information Act lawsuit for records related to the CBP policy showed that about 6,600 travelers had their electronic devices searched at the U.S. border between Oct. 1, 2008, and June 2 of this year, the ACLU said.

"My goal in working with the ACLU is to prevent this from happening to anyone ever again," Abidor said in the ACLU video.

Between October 2008 and June 2009, CBP confiscated more than 220 devices from travelers, and between July 2008 and June 2009, the agency transferred data found on travelers' devices to other agencies more than 280 times, the ACLU said.

The ACLU filed the lawsuit seeking information on border searches in August 2009. The Electronic Frontier Foundation and the Asian Law Caucus filed a similar lawsuit seeking information about the policy in early 2008.

The U.S. Department of Homeland Security, the parent agency of CBP, issued new guidelines for border searches in August 2009, a day after the ACLU filed its lawsuit seeking information about the policy. The new guidelines set limits on how long CBP and sister agency U.S. Immigration and Customs Enforcement could hold onto electronic devices, but it continued to allow searches of devices without suspicion of wrongdoing.

Members of both NACDL and NPPA have also had their devices, including cameras and smartphones, searched at U.S. borders, the ACLU said in a press release. The lawsuit describes CBP searches of a laptop owned by a criminal defense lawyer and a laptop owned by a freelance photographer.

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantusG. Grant's e-mail address is grant_gross@idg.com.