Two agents are resigning and another has been fired, a government official said, bringing to six the number of agency departures. The 12th employee has been placed on administrative leave following the events at a hotel last week in Colombia before President Barack Obama arrived for a summit meeting.
The director of the secret service, Mark Sullivan, went to the White House on Friday night to brief Obama.
The developments came as the agency's reputation took another battering when it was disclosed that one of the agents involved posted pictures on Facebook of Sarah Palin accompanied by a sexually suggestive comment.
The security service supervisor, David Chaney, had been assigned to protect her during the 2008 presidential campaign while she was John McCain's vice-presidential running-mate.
The photographs show Chaney in the background at a car door with Palin in the foreground. In a comment under one of the pictures, Chaney wrote: "I was really checking her out, if you know what I mean?"
Palin, interviewed on Fox on Thursday night, responded angrily. "Well, this agent who was kind of ridiculous there in posting pictures and comments about checking someone out. Well check this out bodyguard: you're fired."
Chaney, 48, was allowed to take early retirement this week in the aftermath of the Colombia prostitution scandal.
Another of the secret service supervisors forced out was named as Greg Stokes, an assistant special agent who ran the bomb-sniffing canine unit, who has been fired, though he is contesting this.
The identities of Chaney and Stokes were revealed by the Washington Post, which also disclosed the Facebook posting.
Both had worked for the secret service for two decades. A third, more junior, agent who has also been ousted has not yet been named.
Eight mores officers under investigation have been placed on administrative leave and have had their security clearance suspended. Also under investigation are 10 military staff.
The scandal involved 11 officers and supervisors and at least 11 military members who were working on security before Barack Obama arrived. The Pentagon acknowledged Friday that an 11th military person, a member of the army, was implicated in the scandal.
The secret service were in Cartagena to help protect Barack Obama while he was attending a summit.
The release of the names of those linked to the partying in Colombia has added fresh momentum to calls by Congress for punitive action against those involved and for investigations into the secret service culture.
Members of Congress, after being briefed by the secret service, predicted more sackings or early retirals could follow. Pete King, Republican head of the House homeland security committee, said: "Several more people will be pushed out."
Also disclosed in the last 24 hours is the identity of the escort whose row over payment led to night of partying becoming public, Dania Suarez.
About 20 women are being interviewed. Conflicting versions are emerging, with some saying some of the women involved had not sought payment. The story came to light when Suarez created a scene, claiming she had been promised $800 but was offered much less.
Lawrence Berger, a lawyer representing Chaney and Stokes, complained to Reuters about "trial by mob". He said Stokes will vigorously defend himself from the accusations.
The Chaney Facebook comment about Palin will cause secret service almost as much embarrassment as the Colombia incident, in part because of the revelation that he viewed her as a sex object but also because he breached the code that bodyguards remain discreet.
Chaney made the comment apparently in response to comments from others on his Facebook page.
