The team of account people and creatives, who all worked on General Mills brands including Cheerios, Wheaties and Green Giant, quit after the departure of Burns, who ran the $200m-plus (£105.5m) global General Mills account.
Burns is under contract to Saatchis until March 15 and has refused to answer any questions due to contract stipulations. He has said though he was fortunate enough to have "opportunities to consider".
An Interpublic spokesman also declined to comment, although speculation has centred on the team forming a New York office of Interpublic's Campbell Mithun, whose clients include General Mills, or a unit within one of the larger global networks.
Burns, who had been with the Publicis Groupe-owned agency for 25 years, was the joint chief executive of Saatchi & Saatchi New York until last September.
However, he was replaced by worldwide CEO Kevin Roberts, who hired executive creative director Tony Granger and Arnold Worldwide's Mary Baglivo to take over the running of the agency, leaving Burns to step back to the role of managing the General Mills account.
Saatchi & Saatchi said it is confident it can hang on to the General Mills account.
"We will continue partnering with it to create big ideas that transform General Mills' brands and take the business to even greater heights," the agency said.
Sources said the employees resigned on Monday, three days after Baglivo and Granger said in an agency memo that Burns was "leaving" and "looking forward to the prospects of other life and career opportunities".
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