Obama to Scouts: What are you doing in my yard?

Melanie Eversley | USA TODAY

Show Caption Hide Caption Girl Scouts camp out on White House's south lawn The Obamas invited a group of about 50 Girl Scouts to camp out on their lawn to promote Michelle Obama's Let's Move Outdoors campaign, an offshoot of the Let's Move campaign that is designed to get young people to exercise more outdoors.

The president and first lady decided to practice a new kind of security tactic when they ran into about 50 intruders on the White House South Lawn on Tuesday night.

They joined them.

About 50 Girl Scouts were making themselves at home on the White House lawn, sitting around a makeshift campfire of electric lanterns, when the Obamas showed up.

"What are you guys doing in my yard?" the president demanded of the giggling interlopers, who are rising fifth-graders. "When did you guys show up?"

The campout was actually a planned event for the "Let's Move Outside" campaign. The camp is an offshoot of Michelle Obama's "Let's Move" program and is designed to get young people to exercise more outdoors.

So instead of rallying the Secret Service to give the little girls the boot onto Pennsylvania Avenue, President and Mrs. Obama parked themselves on separate bales of hay and bantered about with the little security risks. The girls sang camping songs, the first couple listening.

The president told the scouts that they sounded "pretty good" and asked whether they noticed that Mrs. Obama was "rocking out."

Sadly, weather conspired to end the event early. Heavy rains and thunder rolled in and organizers moved the kids and their chaperones into a conference room in the office building next to the White House.

Photos: Girl Scouts take over White House lawn

On a more serious note, the president hailed the campout, saying it would help young people understand that being outside in nature was more important than sitting inside and watching TV. The first lady's office called the event the first ever White House campout – and it fit well into her campaign against childhood obesity.

The girls were from Girl Scout councils in Maryland, Virginia, West Virginia, Washington and Oklahoma. They also were to take part in rock climbing, tying knots and pitching tents.

While the girls were preparing for their night of activity, the president said he unfortunately couldn't remain for all the fun and games.

"I've got to work. I'm not allowed to have fun," President Obama told the group, who then gave him a group hug.

Contributing: David Jackson; The Associated Press