A federal appeals court has for the first time ruled that a warrant is required for the government to obtain an individual’s stored cellphone location records.

The Thursday decision by a three-judge panel in the U.S. Court of Appeals for the 11th Circuit in Atlanta contrasts with a July 2013 decision by another appeals court that a warrant is not required.

That circuit court split increases the likelihood that the issue — one of the most pressing in privacy concerns in the digital age — will be settled by the Supreme Court.

“We hold that cell site location information is within the subscriber’s reasonable expectation of privacy,” the panel wrote in its decision. “The obtaining of that data without a warrant is a Fourth Amendment violation.”

In this case, a criminal defendant named Quartavious Davis appealed a 2012 conviction for robbery and conspiracy in part on grounds that the cellphone tower records were obtained on a court order using a lesser legal standard than a warrant.

Rather than “probable cause,” prosecutors needed to show only that there were “reasonable grounds to believe” that the records sought were “relevant and material” to a criminal investigation.

The panel upheld Davis’s conviction, however, ruling that the officers “acted in good faith reliance” on the court order issued by a magistrate judge.

Cell tower location records were used to place Davis and five others near the scenes of several robberies, including at a restaurant, a gas station and a drug store.

The government argued that historical cellphone tower data is less precise and less invasive than data from phones with GPS technology and therefore deserves less protection than a warrant.

“That information obtained by an invasion of privacy may not be entirely precise does not change the calculus as to whether obtaining it was in fact an invasion of privacy,” the court wrote.

“The appeals court’s opinion is a resounding defense of the Fourth Amendment’s continuing vitality in the digital age,” said American Civil Liberties Union Staff Attorney Nathan Freed Wessler, who argued the cellphone issues before the panel in April. “It puts police on notice that when they want to enlist people’s cellphones as tracking devices, they must get a warrant from a judge based on probable cause” that the records will provide evidence of a crime.

“We are reviewing the decision and considering our options,” said Justice Department spokesman Peter Carr.

The department has previously acknowledged the unsettled nature of the law. “Pending resolution of this issue, each U.S. attorney’s office adheres to the legal requirements of their district as set forth in case law or court decisions and precedent,” Carr said in a statement.

“If we believe the use of any technology or technique may provide information on an individual while that person is in a location where he or she would have a reasonable expectation of privacy, it is our policy to obtain a search warrant,” he said.

The appeals court opinion will apply to all districts within the circuit, which includes U.S. attorneys’ offices in Florida, Georgia and Alabama.