WASHINGTON – The White House was put on lockdown and Lafayette Square was evacuated on Thursday afternoon after a man who allegedly attempted to fly a small drone over the White House fence was detained by Secret Service officers, according to eye witnesses.

A witness, Philipos Melaku-Bello, a 53-year-old peace activist who has regularly protested in front of the White House, said some 400 tourists and onlookers in the area in front of the White House and in the park across Pennsylvania Avenue were moved away to beyond H Street NW.

The man believed to be operating the drone was cooperative with the officers as they checked his pockets and possessions. He was later taken into custody.

The drone was described as between a foot-and-a-half to two feet in size.

The White House itself was put on lockdown for over an hour. President Barack Obama wasn’t there; he was at Camp David in Maryland hosting a meeting with leaders of the Gulf Cooperation Council for the day.

People were allowed back into the park area after by mid-afternoon, about an hour and 45 minutes after the incident.

It was the second drone incident at the White House this year. On Jan. 26, a drone flown by an off-duty government intelligence agency employee crashed into a tree on the South Lawn. The man had been drinking and later turned himself in to authorities. No charges were filed against him.