- The White House says Obama has confidence in the Secret Service chief
- "It has overshadowed us a little," a Colombian official says
- A senator and the Secret Service disagree on the exact number of prostitutes
Washington (CNN) -- A Colombian official said the Secret Service sex scandal has overshadowed the country's effort to showcase the city of Catagena during the recent Summit of the Americas.
"The inappropriate conduct of the Americans, it has overshadowed us a little," said Cartagena Interior Minister Nausicrate Perez. "But we are sure that we will transcend this because Cartagena is much more. It is a beautiful, calm city, a historic city that showed the world its security and tranquility."
Perez said officials are waiting to get more information on the allegations that Secret Service agents brought prostitutes back to their hotel in Colombia ahead of U.S. President Barack Obama's visit to the summit over the weekend.
"We are waiting for a report from the foreign ministry because officially the district of Cartagena does not have evidence that shows that there are people or women from Cartagena involved," Perez said.
Secret Service sex scandal widens 
Lawmaker: Scandal harms Secret Service 
Obama calls for Secret Service probe Meanwhile in the United States, the fallout from the incident continued Tuesday, with the White House defending the Secret Service and its director.
Eleven Secret Service members have been implicated in the investigation, which began Thursday after one of the women complained that she hadn't been paid. In addition, as many as 10 U.S. military personnel from all branches of the armed forces are being questioned about potential involvement in any misconduct, two military officials told CNN.
The Americans were in Cartagena to prepare for Obama visit, and the president has said he expects a "rigorous" investigation.
The investigation is being led by Secret Service Director Mark Sullivan, who has been briefing members of Congress.
A leading senator said Tuesday she had been told as many as 21 women had been involved, and questioned whether the incident could have endangered the president.
"Who were these women? Could they have been members of groups hostile to the United States? Could they have planted bugs, disabled weapons, or in any other (ways) jeopardized security of the president or our country?" asked Maine's Susan Collins, the ranking Republican on the Senate Homeland Security and Governmental Affairs Committee.
That account was disputed by U.S. Secret Service spokesman Ed Donovan who said the exact number of women was still under investigation.
A source familiar with the investigation said, "Senator Susan Collins in a conversation with the Secret Service was told that 21 U.S. personnel are involved in the investigation and she evidently misconstrued that to mean that 21 prostitutes were involved."
Collins' office disagreed with that account saying: "There was no misunderstanding."
Later, Kevin Kelley, a spokesman for Collins, told CNN, "It's outrageous that the department is arguing about the number when, clearly, this incident never should have happened in the first place."
The Secret Service agents and officers involved range in experience from relative newcomers to nearly 20-year veterans, and all have been interviewed at least once, two government officials with knowledge of the investigation told CNN on Monday.
Their security clearances have been pulled while the investigation is under way and could be reinstated if they are cleared, the officials said.
The agents were offered an opportunity to take a polygraph test, according to a U.S. official.
Some of the agents and military personnel maintain they didn't know the women were prostitutes, the official told CNN.
"Even if they weren't (prostitutes), it was totally wrong to take a foreign national back to a hotel when the president is about to arrive," Rep. Peter King, R-New York and the chairman of the House Homeland Security Committee, told CNN's "Piers Morgan Tonight."
House Oversight Committee Chairman Rep. Darrell Issa, R-California, said he thinks the agents should take the polygraph tests, if they haven't already done so.
"For these individuals, if they want to have any career at all, they have to decide on telling the entire truth and seeing whether they have something going forward."
Issa said his level of confidence in Sullivan is "high."
While soliciting prostitution is legal in certain areas of Colombia, it is considered a breach of the agency's conduct code, the government sources said. Military law also bars service members from patronizing prostitutes, displaying conduct unbecoming an officer or, for enlisted personnel, conduct "prejudicial to good order and discipline."
The military personnel involved were sent to Colombia to support the Secret Service. A military official who spoke on condition of anonymity due to the ongoing investigation told CNN that two of those being questioned are Marines who handle military working dogs. Air Force and Navy personnel, some of whom are believed to be explosive disposal experts, also are being questioned, the official said.
The alleged misconduct occurred before Obama arrived in Cartagena, and the Secret Service said the personnel involved were relieved of duty and sent home before the president landed. But the news broke while he was there -- and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, told reporters at the Pentagon on Monday that the incident distracted attention "from what was a very important regional engagement for our president."
CNN's Bob Kovach, Fernando Ramos, Barbara Starr, Jessica Yellin, Deirdre Walsh and Ted Barrett contributed to this report.
