WASHINGTON, D.C. - Planning a visit to the White House? Bring your kids and camera. But please, don't feed the animals.
The Secret Service has started deploying specialized canine units to help protect the area around the White House grounds, where tourists flock day and night to catch a glimpse of 1600 Pennsylvania Ave.
Although the Secret Service has used police dogs since 1976 to screen areas for presidential visits, this is the first time they're being broadly deployed among the general public.
A Uniformed Division Secret Service police officer patrols with a dog as visitors walk on Pennsylvania Avenue in front of the White House in Washington, D.C.,?July 9.
The stepped-up pooch presence started last month as part of the Secret Service's ongoing efforts to innovate and address changing threats, said Secret Service spokesman Ed Donovan.
"This is just one of the proactive, visible security methods being utilized," he said.
In the past, the Secret Service has exclusively used Belgian Malinois dogs, known for being agile, good workers and effective at detecting explosives. But the new program uses a variety of non-Malinois breeds.
That's because these dogs must have a particular temperament suitable for use in public crowds, officials said.
On steamy summer mornings, the new class of canines can be seen patrolling just outside the White House gates, sniffing their way through the throngs of visitors, protesters and joggers passing by.
"Please do not attempt to touch or pet these animals while they are working," reads a banner posted nearby.
The Secret Service isn't saying how many canines are being deployed, but dogs are on hand around the clock.
The Secret Service said the program isn't a response to a specific threat, but a general security enhancement long in the works.
Other public safety agencies like the Transportation Security Administration and the Amtrak Police have long deployed canines in public places.
Those dogs undergo extensive training to recognize and pinpoint odors associated with explosives. Amtrak said it uses Labradors and German shepherds.