WILMINGTON, Del. (Reuters) - U.S. officials at ports of entry improperly contend they are entitled to confiscate and search travelers’ cellphones and other devices without warrants to enforce laws that cover more than customs and immigration, according to a court filing by civil rights groups on Tuesday.

According to documents filed in U.S. District Court in Boston, top immigration and customs officials take the position that they have broad investigative authority.

For instance, David Lee Denton, an official with Immigration and Customs Enforcement (ICE), said in a deposition that border officers could look through emails, social media posts and text messages to help in a range of investigations.

“So perhaps in a fraud investigation, one business might want to report their competitors for engaging in fraudulent business practices,” Denton said in his deposition. “And that would be a factor that might give an agent reasonable suspicion for a border search.”

The American Civil Liberties Union and the Electronic Frontier Foundation, a privacy group, are suing the U.S. government and challenging that authority, which they say could lead to unconstitutional warrantless searches of devices at borders and airports.

The Department of Homeland Security did not immediately respond to a request for comment.

The civil liberties organizations represent 11 plaintiffs who sued in 2017 alleging searches of their electronic devices at ports of entry violated the U.S. Constitution’s protections against unreasonable searches and seizures.

Generally in the United States, law enforcement is required to obtain a warrant before it can search an American’s electronic devices.

But a so-called border search exception, which dates to the early days of the United States, allows authorities to conduct searches at a port of entry without a warrant. That exemption has been repeatedly upheld by the courts.

The rights organizations said customs and immigration officials also act on requests from other agencies as well as state and local police and foreign law enforcement agencies, according to the court papers.

The groups asked U.S. District Judge Denise Capser in Boston to order a halt to such practices without going to trial.

Customs and Border Patrol searched 33,295 electronic devices in fiscal year 2018, up from 5,085 in fiscal 2012, according to the court documents.