The U.S. Secret Service is investigating a small drone found on White House grounds early Monday morning.

The commercial drone was identified as a 'quad copter,' often used by military and law enforcement agencies for surveillance and reconnaissance missions. "The relatively cheap unmanned aerial vehicles are also often used by amateur model aircraft enthusiasts," notes The Hill.

The Secret Service released a statement reading: "On 1/26/15, at approximately 3:08 a.m., a Secret Service Uniformed Division officer posted on the South Grounds of the White House complex heard and observed a 'quad copter' device, approximately two feet in diameter, flying at a very low altitude and ultimately crashing on the southeast side of the complex. There was an immediate alert and lockdown of the complex until the device was examined and cleared."

"An investigation is underway to determine the origin of this commercially available device, motive, and to identify suspects. As additional information becomes available we will update our statement."

President Barack Obama and First Lady Michelle Obama are in India; it was not known whether their daughters were at home when the drone crashed.

USA Today reports:

It is illegal to fly anything in the restricted air space above and around the White House.

The breach occurred as the Federal Aviation Administration develops long-awaited rules for commercial unmanned aircraft.

Congress ordered FAA in 2012 to develop the rules for commercial drones — which can range from a few ounces to as big as an airliner — to share the skies with passenger aircraft. New rules are expected to be announced in September.

In July, Politico reported that Obama was planning to issue an executive order to develop privacy guidelines for commercial drones operating in U.S. airspace, but that there was no timeline for him to do so.