Gov. Dannel Malloy’s administration has filed a federal lawsuit along with the Mohegans and Mashantucket Pequots to allow the Indian tribes to move ahead with their joint East Windsor casino.

The lawsuit, if successful, will put to rest uncertainty over the project caused by the U.S. Department of Interior. That agency is required to review and sign off on the changes to the tribes’ existing gambling compact with the state.

The problem is that the Department of Interior has failed to issue a ruling — something MGM Resorts International, which wants instead to build a casino in Bridgeport, has argued constitutes a denial of the tribes’ plans.

Approval will allow the tribes to team up on the third casino without jeopardizing the slots revenue each pays Connecticut from their respective Mohegan Sun and Foxwoods gambling destinations, built in the 1990s in the southeastern section of the state.

State lawmakers earlier this year approved the East Windsor casino in an effort to compete with MGM’s new development just over the border in Springfield, Mass.

The joint state and tribal lawsuit, which Malloy announced Wednesday, maintains that since the Department of Interior took no action on the East Windsor proposal within 45 days of submission, it should be deemed approved and that decision published in the Federal Register.

“The state of Connecticut over the years has maintained a long-standing partnership and compact with the Mohegan and Mashantucket Pequot tribal nations, and they employ thousands of Connecticut residents at their casinos,” Malloy, a Democrat, said in a statement Wednesday. “State law requires that these compact amendments are in fact approved. That’s why I have asked the Attorney General to file this action. We need clarity and certainty with respect to this issue.”

The state’s legal action comes just a few weeks after U.S. Sens. Richard Blumenthal and Chris Murphy and U.S. Rep. Joe Courtney, all Democrats, wrote Interior Secretary Ryan Zinke asking for his agency’s sign off of the East Windsor project.

Mohegan and Mashantucket chairmen Kevin Brown and Rodney Butler in statements accompanying Malloy’s each expressed frustration with Zinke’s agency.

“The Department of the Interior has a responsibility to Native American tribes, and their failure to act on this issue sets a very dangerous precedent for Indian Country across the United States,” Brown said.

“Despite (a) good faith effort and repeated assurances by the department, their failure to publish our approval letter has forced us to take this action,” said Butler.”

Meanwhile MGM continues trying amass support for its Bridgeport plans, which the company unveiled in mid-September. MGM Chairman and CEO James Murren is the keynote speaker at the Bridgeport Regional Business Council’s annual holiday dinner Tuesday at the Trumbull Marriott.

Uri Clinton, senior vice president and legal counsel for MGM, said “precedent shows that an amendment is not ‘deemed approved’ when Interior returns it, plain and simple. And no lawsuit, not even one backed by the Governor, changes those basic facts.”

Clinton added “We stand by the Bridgeport project and our analysis of where we are in the casino discussion in Connecticut.”

MGM’s interest in Bridgeport has been embraced by Democratic Mayor Joe Ganim, who is has been touting the proposal as he explores a run for governor.

Ganim had tried to bring a casino to town when he was first mayor in the 1990s. Now Republican President Donald Trump at the time was one contender. Zinke is a Trump appointee.

Ganim’s liaison with the legislature, Av Harris, said Wednesday he is “not surprised” that Malloy got involved in the lawsuit.

“I think that instead of focusing on trying to sue in order to create a facility that isn’t really going to attract a lot of people — that’s designed to disrupt business for MGM Springfield — a more productive use of taxpayer resources and time and energy would be to enter into a negotiation with MGM and the tribes,” Harris said. “Everybody sit down in a room and figure out a business environment within which everybody can compete and succeed.”

Blumenthal has backed the lawsuit.

“The court should act promptly to require the Department of Interior to fulfill its crystal-clear legal responsibility and approve this legal agreement between the tribes and the state,” the Senator said in an interview. “A lot of investment hinges on it. Our economy and job creation will be directly affected by it.”

Staff Writer Ken Dixon contributed to this report