Washington (CNN) Secret Service detained a man Thursday afternoon who eyewitnesses tell CNN was trying to fly some sort of remote-controlled aerial device over the White House fence.

The park on the north side of the White House was placed on lockdown while the incident is being investigated. As of Thursday afternoon, the lockdown had been lifted.

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President Barack Obama is not currently in the White House and is at Camp David. Additional details of the incident were not immediately available Thursday afternoon.

It's the second drone incident at the White House this year, coming four months after another man -- a U.S. intelligence agency employee -- lost control of a borrowed personal quadcopter drone that he'd been flying around his apartment, intending to send it out his window and then bring it back inside.