A two-foot-long (half-meter) drone apparently flown by a hobbyist crashed on the White House grounds Monday in an extraordinary, if unintended, breach that raised fresh questions about the president’s security ― and a growing threat from the sky.

A man later came forward to say he was responsible for the mishap in the middle of the night and hadn’t meant to fly the drone over the complex, officials said. “Initial indications are that this incident occurred as a result of recreational use of the device,” said Secret Service spokesman Brian Leary.

President Barack Obama and his wife, Michelle, were overseas when the quadcopter struck the southeast side of the grounds at about 3 a.m. Daughters Sasha and Malia stayed behind in Washington; it was not known whether they were at the mansion.

Officials believed the intrusion to be the first of its kind on the White House grounds, although not the first in the vicinity.

Low-flying drones like the quadcopter ― a device lifted by four propellers ― have become increasingly sophisticated and affordable instruments that authorities worry could also become tools for terrorists or others meaning to do harm.

It was not immediately clear that the Secret Service could have done anything to prevent Monday’s incident. Yet the episode joins a string of recent security breaches at the White House that have fueled questions about the agency’s effectiveness and ability to protect the president. (AP)