BIRMINGHAM, Ala. (AP) -- Alabama's Republican Party chairman says Newt Gingrich and Rick Santorum have agreed to appear at a forum for presidential candidates Monday in Birmingham.

Chairman Bill Armistead said Ron Paul and Mitt Romney have been invited to the event at the Alabama Theater. The event is free and seating is on a first-come, first-served basis.

The forum is one day before Alabama voters go to the polls for the state's primary election. Mississippi's primary is the same day. The Republican chairman said the two Deep South primaries will have a significant impact on selecting the party's presidential nominee.