(Photo Credit: Win McNamee/Getty Images)

A dramatic scene unfolded at the White House today as Secret Service agents raced to confront and apprehend a young man who broke the security perimeter.

"Drop down! Drop down!" Secret Service officers shouted, as they rushed across the North Lawn, their guns at the ready.

A man had jumped over the North Fence, triggering an urgent security response and causing the White House to be put on lock down.

The man, who appeared to be in his 20s, wearing a gray T-shirt, dark shorts and a yellow Pokemon hat, sat on his knees on the grass. He resisted calls for him to lie down and was forcibly pushed and held to the ground by an agent, who quickly patted him down.

As the man was held, face down on the lawn, a large canine, held on a leash by another agent, barked frantically in the man's face.

Moments later, the man, whose name has not been released, was led off the lawn, his hands cuffed, his head hanging low.