That small drone you got for Christmas may soon need a license plate of sorts.

U.S. aviation regulators said they intend to require for the first time that drone owners place a government-assigned ID number on the outside of the devices, according to a little-noticed filing earlier this month.

Current rules require drone owners to register with the Federal Aviation Administration and more than 1 million people have done so. They must identify their drones, but the marker can be placed inside battery compartments or other internal areas where it can’t been readily seen.

The FAA’s move is the latest step taken by the agency and U.S. security agencies to bring greater control over the new frontier in flight that has been plagued by rule violations, a handful of collisions with other aircraft and growing concerns about their potential use by terrorists.

“This action would require small unmanned aircraft owners to display the unique identifier assigned by the FAA upon completion of the registration process on an external surface of the aircraft,” the agency said on a White House website that tracks proposed new regulations. “Small unmanned aircraft owners would no longer be permitted to enclose the unique identifier in a compartment.”

Use of unique identifiers is a long-standing requirement for traditional planes and helicopters and they would allow tracking of the growing number of drones.

While he didn’t directly address the latest action, FAA’s Acting Administrator Dan Elwell said at a May 16 forum sponsored by Bloomberg Government the agency can’t tolerate having “unidentified objects” in airspace it controls.

“We need assurances that any drone, any unmanned aircraft, operating in controlled airspace is identifiable and trackable,” Elwell said. “It’s as simple as that.”

The brief description of the proposal on the White House website didn’t include details about how big the markings should be and whether there would be penalties for violations. The FAA didn’t immediately respond to a request for comment.

The FAA at the close of 2016 was preparing to issue regulations allowing expanded drone flights over people’s heads, but that was delayed by the FBI and Homeland Security concerns that unmanned devices could be used by criminals or terrorists. Similar to requiring external markings to identify a drone, the FAA is also crafting a requirement that drones broadcast their identity.