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President Obama, in his first public remarks on the prostitution scandal involving members of the Secret Service, said Sunday that he will be "angry" if the reported allegations against the agents turn out to be true. He said Secret Service personnel, like the rest of any U.S. delegation abroad, must "observe the highest standards."

"We're here on behalf of our people and that means that we conduct ourselves with the utmost dignity and probity. And obviously what's been reported doesn't match up with those standards," Obama said, on the closing day of his visit to Colombia.

The president, though, said he would wait until the internal investigation is complete before rendering a judgment. He said he expects the probe to be "thorough" and "rigorous" -- and that if the allegations turn out to be true, "then of course I'll be angry."

The president addressed the controversy during a joint press conference with Colombian President Juan Manuel Santos. Allegations that a Secret Service unit interacted with prostitutes in Colombia ahead of Obama's visit have overshadowed a trip that was supposed to focus on trade and other pressing issues between the U.S. and its Latin American ally.

Eleven agents accused of misconduct were recalled from their assignment and have since been placed on administrative leave.

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Obama cast the incident as isolated, and praised the Secret Service as a whole.

"These men and women perform extraordinary service on a day-to-day basis protecting me, my family, U.S. officials," he said. "They do very hard work under very stressful circumstances and almost invariably do an outstanding job."

Rep. Peter King, R-N.Y., chairman of the House Homeland Security Committee, took a similar position - praising the way the agency's probe has been conducted and voicing confidence in Secret Service Director Mark Sullivan.

King called the incident an "aberration."

King's panel, though, is moving to look deeper into the incident. He told Fox News that he's directed his staff to launch an "immediate investigation" -- he said his panel will likely hold a hearing on the incident.

Rep. Darrell Issa said Sunday that he believes the potential misconduct is not a first.

"Things like this don't happen once if they didn't happen before," Issa, R-Calif., chairman of the House Oversight and Government Reform Committee, said on CBS' "Face the Nation."

He said his staff will participate in what he described as an "over-the-shoulder investigation" to find out how the incident happened and "how often has this happened before."

"This kind of a breach is a breach in the federal workforce's most elite protective unit," he said.

Issa said he was not satisfied by claims that Obama was never in danger, considering the questions the incident raises.

"What happens if somebody six months ago, six years ago, became the victim of their own misconduct and is now being blackmailed?" he said. "The question is, is the whole organization in need of some soul-searching, some changes."

The Secret Service scandal is the latest example of federal workers coming under the congressional microscope for their conduct. Issa's committee and others are also opening a probe into the General Services Administration after an internal report found the agency spent more than $820,000 on a Las Vegas conference.

Issa said Sunday that Americans need to have confidence in federal workers, whether they're from the GSA or the Secret Service. Issa also said he thinks the number involved in the Secret Service controversy "might be higher" than disclosed.

Aside from the Secret Service agents, five members of the U.S. military also "may have been involved in inappropriate conduct" in the same hotel, military officials said Saturday. A military statement did not get into specifics, but said they violated curfew.

Details are still emerging, but the behavior of the agents initially attracted attention during a dispute at the Hotel Caribe over payment for an extra "guest."

According to a senior law enforcement official, an employee approached at least one Secret Service agent and demanded that he pay extra money for having an additional overnight guest in his room.

The agent balked, which eventually resulted in a confrontation and forced diplomatic intervention.

The official said the guest involved apparently was a prostitute.

Afterward, a new Secret Service crew was immediately rushed to Colombia to cover the agents who had been sent home.

The embarrassing incident has quickly eclipsed issues addressed at the summit such as foreign trade, the economy, drug trafficking, immigration and collaboration among the 33 Western Hemisphere countries.

The beachfront hotel where the apparent incident occurred is also the same where other White House staff and the press are staying.

A Service Service spokesman said the alleged incident occurred prior to the president's arrival.

Fox News' Ed Henry and Kimberly Schwandt contributed to this report.