The two Massachusetts candidates in a closely-watched and hard-fought race for a U.S. Senate seat will not engage in a fourth debate before Election Day, the debate sponsor announced Tuesday.

A final faceoff between Republican Sen. Scott Brown and his Democratic challenger, Elizabeth Warren, was originally scheduled for Tuesday evening, a week out from the election.

Both candidates withdrew from the Tuesday debate on Monday afternoon, as Superstorm Sandy ravaged the East Coast. At CNN's last count, over 262,000 customers in Massachusetts were among the nearly 8 million without power as a result of Sandy.

Debate sponsor the Boston Media Consortium, which included several local and regional television, radio stations, and a newspaper, postponed the debate. But Tuesday, the consortium said the debate was off.

"The campaigns could not agree on a new date, so the debate will not take place," it said in a statement.

Brown's communications director pointed out in a statement that his candidate had planned a bus tour which will take him through election day.

"It is unfortunate that nature intervened in a way we all agreed made it inappropriate to carry on with the scheduled debate," Colin Reed said. "With only days remaining in the campaign, and with a long-planned bus tour kicking off Thursday through Election Day that will take Scott Brown to every corner of the Commonwealth, our calendar simply cannot accommodate a rescheduling of this fourth debate and the planning and preparation that would go into it."

Warren's campaign manager, Mindy Myers, also described the cancelation as "unfortunate" and blamed Brown for "ducking questions."

"It is unfortunate voters will not have the chance to hear from both candidates on the important issues facing Massachusetts. Elizabeth was working with the debate organizers to move forward on Thursday. Unfortunately but not surprisingly, Scott Brown is again ducking questions about his record," Myers said.

The two candidates canceled Monday campaign events, as did the presidential candidates and other candidates for the U.S. Senate.

The Massachusetts race been one of the most expensive races this year, and a week out from the election, polls find the two candidates are in a dead heat.

CNN Chief National Correspondent John King was to moderate the debate.