Boston Mayor Michelle Wu called the Kraft Group's proposed agreement over Revolution stadium an "unserious offer."

Mayor Michelle Wu spoke out against the Kraft Group's proposal for building a stadium in Everett to host the New England Revolutions, calling their mitigation offer to Boston an "unserious proposal" -- criticisms the Revolutions president and Everett mayor pushed back against.

A battle of public opinion escalated Monday near the proposed New England Revolution soccer stadium as Boston Mayor Michelle Wu and Kraft Group leaders traded jabs over their talks.Between the lines: The strained negotiations spilled into public view with Wu blasting the developer for a lack of details about the Everett stadium's potential impact and a $750,