President Barack Obama said the Secret Service prostitution scandal was "a little distracting" but that employees at the center of the investigation were not representative of the agency tasked with protecting him and his family.

Obama said in an interview Tuesday on NBC's "Late Night with Jimmy Fallon" show that "99.9 percent" of the time, members of the Secret Service do a great job and put their lives on the line.

"A couple of knuckleheads shouldn't detract from what they do. What these guys were thinking, I don't know. That's why they're not there anymore," Obama said.

"These guys are incredible. They protect me. They protect Michelle. They protect the girls. They protect our officials all around the world," the president said.

A dozen Secret Service personnel and another 12 military personnel preparing for Obama's visit to Cartagena, Colombia, are being investigated for cavorting with prostitutes. Six Secret Service agents have been let go over the incident and the Defense Department has suspended the security clearances of the military personnel being investigated.

As many as 20 prostitutes were involved with the group, officials say and none are believed to be underage.

The incident broke into public view when one of the prostitutes argued with a Secret Service agent over her payment in a hallway of the Caribe hotel. Local law enforcement intervened on the prostitute's behalf. Paid sex is legal in Cartagena, but violates codes of conduct for U.S. personnel who were working there.