Suffolk Downs has asked Caesars Entertainment to withdraw as a managing partner in the track's bid to build a resort casino in East Boston less than three weeks away from a scheduled referendum vote on the $1 billion proposed gaming resort.

Suffolk Downs Chief Operating Officer Chip Tuttle released a statement Friday evening explaining that the track had asked Caesars Entertainment, which operates casinos around the country from Las Vegas to New Jersey and New Orleans, to withdraw as a qualifier from its casino license application based on concerns raised by a state background check.

The Massachusetts Gaming Commission's investigative bureau has been conducting background checks on casino license applicants to determine suitability to hold one of the three casino licenses to be awarded regionally in Massachusetts. The commission's report regarding suitability was delivered to Suffolk Downs late Friday afternoon.

Tuttle said in his statement that he remains confident that Suffolk Downs will be deemed suitable for licensing, and an official with Suffolk Downs told the News Service that the track intends to push forward with its pursuit of a gaming license, including the Nov. 5 referendum votes scheduled in the host communities of East Boston and Revere.

It was not immediately clear what the Gaming Commission uncovered to cause Suffolk Downs to reconsider its partnership with Caesars, or what Suffolk Downs will do next to secure a partner.

"Based on recent information and the briefing we received from the investigative bureau of the Massachusetts Gaming Commission, we are confident that Suffolk Downs will be deemed suitable for licensing as we work to earn a gaming license in the Commonwealth," Tuttle said in statement. "As a result of the briefing, we have asked our management partner, Caesars Entertainment, to withdraw as a qualifier from our license application."

Tuttle continued, "We will immediately begin a public communications initiative to notify our host communities of this change. We look forward to the next phases of the public process to bring to fruition our proposal to develop a world class destination resort casino on our 161 acre property that will be an economic generator for our two host communities of Boston and Revere."

Suffolk Downs is competing for the sole eastern Massachusetts casino license with developer Steve Wynn, who has proposed a casino on the Mystic River in Everett, and a Foxwoods development in Milford.

Officials from both Suffolk Downs and Caesars were on hand in August to announce the signing of a host community agreement with Boston Mayor Thomas Menino guaranteeing $32 million in annual payments to the city, with the potential for payment to rise to $52 million if the casino at Suffolk Downs meet its $1 billion annual gaming revenue projections.

The developers - Suffolk Downs and Caesars Entertainment - also agreed to make a $33.4 million upfront payment to East Boston to start a neighborhood business program, to build a new youth and senior citizen community center, and to make improvements to a school and two East Boston parks.

The development, as proposed, would include two gaming areas, two 450-room hotels, restaurants, retail and a seven-story parking garage.

Officials from both Suffolk Downs and Caesars have been hosting employment forums in recent weeks to inform residents of East Boston and Revere about the job opportunities that will be created if the partners were successful in their bid for a casino license.

Caesars Entertainment President for Central Markets and Partnership Development John Payne was also appointed this fall to a three-year term on the board of directors at the Greater Boston Convention and Visitors Bureau.

At the time, Bureau President Patrick Moscaritolo said, "John developed the model for integrated city casinos in New Orleans, where the company partners with local hotels, restaurants and visitor attractions. Caesars and Suffolk Downs' desire to replicate this model in Boston will mean new joint marketing opportunities for our members and new business for our city."