WASHINGTON (AP) - The drone-control debate has hit uncomfortably close to home for the White House, thanks to an apparently hapless operator who sent his quadcopter crashing inside the presidential compound.

WASHINGTON (AP) The drone-control debate has hit uncomfortably close to home for the White House, thanks to an apparently hapless operator who sent his quadcopter crashing inside the presidential compound.

Questions persist about why the night-owl drone operator would be flying it within range of the White House at 3 a.m. but the Secret Service's early investigation suggested he meant no harm. Even so, the crash inside the compound Monday pointed to the risk of increasingly commonplace drones penetrating the presidential security bubble, with more dangerous intent. And it highlighted the challenge of setting controls on this expanding frontier.

President Barack Obama and his wife, Michelle, were overseas when the quadcopter a two-foot-long craft with four propellers struck the southeast side of the grounds. Officials believed the intrusion to be the first of its kind on the highly fortified property, although not the first in the vicinity.

Authorities locked down the White House for several hours in a vigorous emergency response, only to have the unidentified man step forward to own up to a big mistake.

The episode unfolded with the Obama administration on the verge of proposing rules for drone operations that would replace an existing ban on most commercial flights. Only a small number of companies can use them for inspections and aerial photography.

Hobbyists can fly them, but must keep them under 400 feet in altitude, 5 miles from an airport, always within sight and not within a highly populated area. The drone operator clearly violated the rules, and in a zone designated as protected air space around the White House.

Monday's episode "complicates the administration's messaging that commercial drones can be introduced smoothly without concern over safety, security and privacy," said Kenneth Quinn, a former Federal Aviation Administration general counsel. The FAA has estimated 7,500 commercial drones will be in the skies within five years of the coming regulations taking effect.

That does not count the increasingly inexpensive consumer drones that were a hit for Christmas, far more sophisticated than the remote-controlled toy and hobby airplanes out for decades.

Whether a quadcopter can carry and fire a weapon depends upon how robust the drone is and how lightweight the weapon. Most commercially manufactured quadcopters are small, weighing 2 to 5 pounds and measuring 1 to 3 feet in length.

Paul McDuffee, vice president at drone-maker Insitu, said of the one that crashed: "Something of that size is going to be very limited in terms of what it can carry, probably down to a few ounces in payload."

Even so, a small drone at low altitude is hard to intercept.

"There's probably nothing they have that could stop it, particularly at night," said James Lewis of the Center for Strategic and International Studies. "The sniper would be shooting at the drone and his bullets would be going past it into the buildings on Connecticut Avenue. If it's a crisis or emergency, sure, that makes sense, but what goes up comes down, and that includes bullets."

The Federal Aviation Administration receives reports across the country nearly every day of drones operating near manned aircraft and airports or over densely populated areas, including multiple times near the White House.

In one, police arrested a man in August who got stuck in a tree at Freedom Plaza, several blocks from the White House, after he climbed to retrieve his drone, according to a compilation of recent incidents by the FAA. In July, a Secret Service patrol detained someone flying a quadcopter drone in President's Park, not far from the White House grounds, and confiscated it.

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Associated Press writers Josh Lederman and Sagar Meghani contributed to this report.