Palmer, Mass. — Voters appeared to have shot down the Mohegan Sun Massachusetts casino proposal in a binding referendum Tuesday, but the outcome remained unofficial pending a likely recount today.

Mohegan Sun officials said problems with a voting machine in one of the town’s four precincts warranted a hand recount.

At a press conference about 90 minutes after polls closed, Mitchell Etess, chief executive officer of the Mohegan Tribal Gaming Authority, said Mohegan Sun would formally request that the town conduct the recount.

Kevin Conroy, a lawyer for the casino operator, said poll watchers witnessed a machine “having problems, not accepting ballots.” He said observers saw ballots being removed from the machine “and some wound up on the floor.”

The irregularities occurred in Precinct Two, where voters rejected the casino plan 836 to 591, a margin of 245 votes.

Overall, the Mohegan Sun Massachusetts proposal was defeated by 93 votes.

The tally was 2,657 to 2,564, with 5,221 voters casting ballots, a turnout of 66 percent, according to the town clerk.

The outcome, if it stands, effectively would end Mohegan Sun’s bid for the sole casino license the Massachusetts Gaming Commission is expected to award for western Massachusetts.

MGM Resorts International’s plan for an $800 million project in Springfield would be the only remaining applicant for license.

“Obviously, we’re disappointed with the results,” said Etess, who thanked supporters and volunteers for “their tremendous effort.”

He said the casino proposal offered Palmer a “once-in-a-lifetime opportunity.”

Town Manager Charlie Blanchard, who waited as the referendum results were posted outside the town clerk’s office at Town Hall, also expressed disappointment with the outcome.

“We had an excellent host community agreement that offered Palmer a great opportunity, but it’s up to the people and the people have spoken,” he said.

Mohegan Sun Massachusetts would have featured gaming and resort amenities, two hotels, a 70,000-square-foot water park and 300,000 square feet of entertainment, dining and retail space.

Elsewhere in Massachusetts, voters in East Boston rejected the Suffolk Downs casino plan proposed for the race track that straddles the East Boston-Revere line.

b.hallenbeck@theday.com