WASHINGTON (Reuters) - The Federal Aviation Administration said on Tuesday it is requiring small drones to display registration numbers on the exterior to address concerns raised by U.S. security officials and to make it easier to identify owners.

FILE PHOTO: A drone hovers at a viewpoint overlooking the Space Needle and skyline of tech hub Seattle, Washington, U.S. February 11, 2017. REUTERS/Chris Helgren

In 2015, the FAA published rules requiring all drones to register prior to operation and that a government registration number be accessible in a battery compartment or other similar location.

The FAA said in a notice published on Tuesday in the Federal Register it is requiring the “registration number to be marked on the exterior of the aircraft.”

The agency said the move is at the request of law enforcement and the FAA’s interagency security partners “regarding the risk a concealed explosive device poses to first responders who must open a compartment to find the small unmanned aircraft’s registration number.”

The new rules take effect on Feb. 23.

The FAA said it first received concerns about drone ID numbers in December 2016 from law enforcement but delayed acting because of lawsuits challenging the drone registration rules. The agency said if it did not act quickly that “first responders could be exposed to additional risk during the notice and comment period as a result of the attention drawn to the vulnerability.”

There are nearly 1.3 million registered drones in the United States and more than 116,000 registered drone operators. Officials say there are hundreds of thousands of additional drones that are not registered.

Congress last year gave the Department of Justice and Department of Homeland Security new powers to disable or destroy threatening drones after officials raised concerns about the use of drones as potential weapons.

Earlier this month, the FBI said authorities confiscated six drones whose owners violated a temporary order not to fly the devices in the Atlanta area ahead of the NFL’s Super Bowl.

The issue of threats by drones to commercial air traffic came to the fore after London’s second-busiest airport, Gatwick Airport, was severely disrupted in December when drones were sighted on three consecutive days.

Last month, 43 flights into New Jersey’s Newark Liberty International Airport were required to hold after drone sightings at nearby Teterboro airport, while nine flights were diverted.

In January, U.S. Transportation Secretary Elaine Chao proposed rules that would allow drones to operate over populated areas to help speed their commercial use.

The FAA is also working on rules to set remote identification requirements for drones for tracking them.