By Steve Tawa

PHILADELPHIA (CBS) — Mayor Nutter is calling Philadelphia fire commissioner Lloyd Ayers a “dedicated public servant” whom he supports, after the city firefighters’ union called for Ayers resignation in connection with last month’s fatal Kensington warehouse fire.

Firefighters’ Union Local 22 contends that Ayers and his two top deputies were guilty of incompetence and indifference, and should resign or be suspended (see related story).

The union contends there were critical tactical errors made by fire department leaders, including failing to establish a “collapse zone,” resulting in the deaths of Lt. Robert Neary and firefighter Daniel Sweeney (see related story).

Mayor Nutter disagrees with that assessment:

“There were collapse zones established,” the mayor told reporters today.

(Tawa:)   “The union says it has proof that there was not.”

(Nutter:)  “I’m not getting into a back-and-forth.  The answer is the answer.”

The mayor says he won’t get into what he calls “personality battles” between the union leadership and the leader of the Philadelphia Fire Department.

“There are multiple agencies looking into what happened that morning.  When we have all of those details, we’ll be in a better position to discuss it, as opposed to speculating on it,” Nutter said.

The cause of the fire is under investigation, and a grand jury is looking into it as well.