Members of the Secret Service counter sniper team keep watch over US President Barack Obama's motorcade
More agents will be forced out of the Secret Service as early as Thursday, a US lawmaker said, as the White House warned foes not to "politicize" the prostitution scandal blighting the agency.
"It is our understanding the resignations could come today or tomorrow," Republican Peter King, chairman of the House Homeland Security Committee, told AFP, a day after three of the elite presidential protection agency's 11 employees involved were forced to leave.
King did not say how many more agents might lose their jobs over the misconduct, in which the agents as well as 10 military personnel allegedly cavorted with prostitutes at a hotel in Cartagena, Colombia where President Barack Obama was attending a regional summit.
But congressman Elijah Cummings, the ranking Democrat on the House Oversight and Government Reform Committee, said there was "absolutely no doubt" that the rest of the agents involved will resign or be dismissed.
"Why? Because of the culture" of the agency, Cummings told CNN.
"They have this pride. They don't want any bad apples, and so they probably will leave."
With the Secret Service under the microscope -- and lawmakers preparing to probe the agency in a hearing next week -- Republican Senator Jeff Sessions called on Obama to "assert discipline" in the wake of the sleazy episode.
"I believe that the president of the United States is the chief executive officer for the entire governmental bureaucracy," said Sessions, mentioning another scandal that was sparked when details emerged this month over excesses at a Las Vegas conference held by the General Services Administration.
"The president needs to assert discipline, management directions throughout the executive branch, and presidents are to be held responsible."
Obama's spokesman Jay Carney declined to pass judgment on the events in Colombia, but he dismissed the complaint by Sessions.
"This sounds very much like a lawmaker attempting to politicize something that is not at all political," Carney said.
Obama's spokesman also repeatedly declined to pass judgment on Secret Service management and practices, other than repeating that the president would be "angry" if the allegations turned out to be true.
"The investigation is still under way. So we'll await the results of that investigation," he said.
Senate Majority Leader Harry Reid said the Senate Judiciary Committee "will hold hearings on this," but expressed a note of exasperation over agents who were supposed to be among the most disciplined in federal service but who instead proved to be a major embarrassment.
"There is not a committee hearing that's going to... stop people from being stupid," Reid said.
"People that are here to protect the president will go to Colombia and have a fight with a prostitute over how much she should be paid? That's either very stupid or a total lack of common sense," he added.
Around 20 women are said to have been invited back to a hotel in the Caribbean resort of Cartagena by agents and military personnel preparing for the arrival of Obama at a weekend Summit of the Americas.
Cummings and Republican Darrell Issa, who chairs the House oversight committee, meanwhile expressed concern in a Wednesday letter to Secret Service director Mark Sullivan that the agents at the center of the allegations may have been careless with "sensitive security information."
They called on Sullivan to provide in-depth details about exactly what happened, including a timeline of events and accounts by all personnel involved, and details of any misconduct by agents on overseas trips dating back to 2007.