SPRINGFIELD, Mass. (AP) — The city of Springfield will not hold a casino referendum on the same day that Massachusetts voters go to the polls to elect a new U.S. senator, Mayor Domenic Sarno announced on Tuesday.

City officials have been negotiating host community agreements with two prospective casino developers in the city and had hoped to put one or both proposals before voters on June 25. Having the referendum coincide with the June 25 special election to fill the Senate seat formerly held by John Kerry would save on election costs for the city, and possibly bring a stronger voter turnout.

But in order to schedule the casino referendum on June 25, the city would have had to wrap up host community negotiations with the developers and have them approved by the city council by Thursday, so as to provide the required two-month notice of the election.

Sarno said Tuesday that while negotiations were close to completion, they would not be done in time to accommodate the timetable.

Companies affiliated with MGM Resorts International and Penn National Gaming have offered separate proposals, each calling for $800 resort casinos in Springfield, the largest city in western Massachusetts.

Voter approval of host community agreements is required before developers can apply to the state's gambling commission for the sole western Massachusetts resort casino license. There are two other casinos proposed for the region, one in West Springfield and one in the town of Palmer.