NEW YORK (AP) _ A strike threat by workers at the famed Apollo Theatre threatened Monday night's presidential debate between Al Gore and Bill Bradley, with the vice president vowing Saturday not to cross a picket line.

The union workers, who have been without a contract since September, announced they would strike at noon Monday unless they had a new deal in place.

The Bradley-Gore face-off, focusing on race and urban issues, was the only scheduled head-to-head New York meeting between the Democratic candidates before the state's March 7 primary.

It was billed as one of the biggest debates of the primary season.

Union workers charged that the theater was not negotiating in good faith, and demanded reinstatement of a fired shop steward.

``Our intentions are not to halt something important to the American public,'' said James Claffey, business manager of Local 1 of the International Alliance of Theatrical Stage Employees. ``But we have to use this window of opportunity for the best interests of our members.''

The union represents 34 stagehands responsible for sound, lighting, scenery and other theatrical elements at the Apollo.

If no deal is reached, the union workers will set up a picket line outside the theater. Crossing the line would likely alienate a traditional Democratic voting bloc, organized labor.

Gore spokesman Peter Ragone said Gore would not cross a picket line.

A Bradley spokesman did not return a call for comment.

Calls left Saturday at the Apollo Theatre Foundation for executive director Grace Blake also were not returned.