A device, possibly an unmanned aerial drone, was found on the White House grounds during the middle of the night while President Barack Obama and the first lady were in India, but his spokesperson said on Monday that it posed no threat.
It was unclear whether their daughters, Sasha and Malia, were at home at the time of the incident with their grandmother, Marian Robinson, who also lives at the White House. The White House had said before the president's trip that the daughters would remain in Washington so not to miss school.
The Secret Service had no immediate comment on what it found.
Obama's press secretary, Josh Earnest, speaking in New Delhi, did not deny that the object found at the White House was an aerial drone. Drones come in various sizes, some quite small, with purposes ranging from surveillance to recreational toys.
"There is a device that has been recovered by the Secret Service at the White House," Earnest said when asked if a drone was found. "The early indications are that it does not pose any sort of ongoing threat to anybody at the White House."
Police, fire and other emergency vehicles swarmed around the White House in the predawn hours, with several clustered near the southeast entrance to the mansion. The White House was dark and the entire perimeter was on lockdown until around 05:00, when those who work in the complex were allowed inside.
Obama and his wife, Michelle, were the featured guests on Monday at a parade celebrating India's Republic Day. They planned to stop in Saudi Arabia on Tuesday before returning to Washington.
While the circumstances of this incident were not immediately clear, previous security breaches at the White House have led to questions about the Secret Service's effectiveness.
Four highest-ranking executives were reassigned this month, and former director Julia Pierson was forced to resign last year after a Texas man armed with a knife was able to get over a White House fence in September and run deep into the executive mansion before being subdued.
An independent panel that investigated the agency's leadership and practices in the wake of the September incident and the disclosure of a previously unreported security breach that month recommended hiring a new director from outside the agency.
That report was the second critical review of the agency responsible for protecting the president. In November, the Homeland Security Department, which oversees the Secret Service, released an internal investigation about the fence-scaling incident that found poor training, staff and a series of missteps led to the breach.
Homeland Security investigators found, among other things, that uniformed agents patrolling the White House grounds the night of 19 September mistakenly assumed that thick bushes near the mansion's front door would stop the intruder.