CHICAGO (AP/CBS) — Chicago Public Schools’ new CEO says she’s willing to commit to a five-year moratorium on school closures starting in the fall — if the district can first “right-size” its classroom space, which now has about 100,000 excess seats.

Schools CEO Barbara Byrd-Bennett said Monday the plan depends on Illinois lawmakers allowing an extension on a deadline for announcing proposed school actions. Byrd-Bennett wants a one-time extension of the deadline from Dec. 1 to Mar. 31 .

Byrd-Bennett made the announcement during a speech in Chicago.

Mayor Rahm Emanuel says he supports the moratorium and acknowledges “too much uncertainty” around school changes in past years.

The mayor promises Chicago citizens will be involved in discussing school changes this year. A nine-member commission will hold public hearings about space usage in the district.

The Chicago Teachers Union voiced opposition to Byrd-Bennett’s proposal.

“Today’s announcement is nothing more than a sleight of hand on behalf of the school district.  CPS school actions target communities of color.  How can the district cry ‘under-utilization’ as a justification for school closings while it simultaneously approves the opening of new charter campuses?” CTU president Karen Lewis said in a written statement.

(TM and © Copyright 2012 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright2012 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)