WASHINGTON – Moving swiftly, the Secret Service forced out three agents Wednesday in a prostitution scandal that has embarrassed President Obama. A senior congressman welcomed the move to hold people responsible for the tawdry episode but warned “it’s not over.”

The Secret Service did not identify the agents being forced out of the government or the eight others who it said remain on administrative leave. In a statement, it said one supervisor was allowed to retire and another will be fired for cause. A third employee, who was not a supervisor, has resigned.

The agents were implicated in the prostitution scandal in Colombia that also involved about 10 military service members and as many as 20 women.

“These are the first steps,” said Rep. Pete King, R-N.Y., chairman of the House Homeland Security Committee, which oversees the Secret Service. King said the agency’s director, Mark Sullivan, took employment action against “the three people he believes the case was clearest against.” But King warned: “It’s certainly not over.”

King said the agent set to be fired would sue. King said Sullivan had to follow collective bargaining rules but was “moving as quickly as he can. Once he feels the facts are clear, he’s going to move.”

The embarrassing scandal erupted last week after 11 Secret Service agents were sent home from the colonial-era city of Cartagena on Colombia’s Caribbean coast after a night of partying that reportedly ended with at least some of them bringing prostitutes back to their hotel. The special agents and uniformed officers were in Colombia in advance of Obama’s arrival for the Summit of the Americas.

The tawdry episode took a sharp political turn when presumptive Republican presidential nominee Mitt Romney said he would fire the agents involved.

Romney told radio host Laura Ingraham on Wednesday that “I’d clean house” at the Secret Service.

“The right thing to do is to remove people who have violated the public trust and have put their play time and their personal interests ahead of the interests of the nation,” Romney said.