A privacy rights advocacy group told appellate judges Thursday that the use of full-body scanners as a first line of defense at airport security checkpoints is an “unreasonable search” in violation of passengers’ civil rights.

The Electronic Privacy Information Center wants to stop the Transportation Security Administration from using the scan that shows a naked image of a passenger’s body as a primary means of screening. EPIC says the policy is a violation of the Fourth Amendment to the Constitution and laws protecting privacy and religious freedom and is asking the U.S. Court of Appeals in Washington to require the agency to make a new rule with input from the public before it goes into effect.