The news follows the resignation last week of Mike Burns, Saatchi & Saatchi New York's outgoing vice-chairman and long-time General Mills account director.
Doug Moore, General Mills' vice-president of advertising and branding, is also a former Saachis employee.
It has yet to emerge whether the staff quit their jobs with a backer in place.
A Saatchi & Saatchi statement said: "While the recent departures are unfortunate, we remain confident in our ability to service this important client. We will continue partnering with them to create big ideas that transform General Mills' brands and take the business to even greater heights."
.jpg)
.jpg)