(Updated 12:30 p.m.) The same day MGM Resorts International announced plans for a Bridgeport casino, the U.S. Department of Interior sent the chairmen of the federally recognized tribes an ambiguous letter regarding plans for its East Windsor casino.

In identical letters received both by Mohegan Tribal Chairman Kevin Brown and Mashantucket Pequot Tribal Chairman Rodney Butler, Acting Assistant Secretary of the Bureau of Indian Affairs Michael Black, wrote that approval of the amendment was “premature and likely unnecessary.”

However, the legislation Connecticut passed authorizing the two tribes to build a third casino off tribal land in East Windsor requires approval before it can move forward. The East Windsor casino was expected to head off traffic to the new $950 million MGM casino being built in Springfield, Mass. That casino is expected to open in the fall of 2018.

“The Amendment addresses the exclusivity provisions of the Gaming Compact,” Black wrote in a letter dated Friday. “We find that there is insufficient information upon which to make a decision as to whether a new casino operated by (the tribes) would or would not violate the exclusivity clauses of the Gaming Compact. The Tribes have entered an agreement with the State whereby they have agreed that the exclusivity provisions will not be breached by this arrangement. Therefore, our action is unnecessary at this time.”

The letters were copied to two Nevada lawmakers — U.S. Sen. Dean Heller and U.S. Rep. Mark Amodei, both Republicans. U.S. Sens. Richard Blumenthal and Chris Murphy, both Democrats, were not copied.

A spokeswoman for Attorney General George Jespen said they are reviewing the letter “in consultation with relevant policymakers. We would decline to comment further at this time.”

The state asked the Bureau of Indian Affairs for approval of the amendment back in July. Based on a previous letter from an Interior Department official the tribes felt approval of the amendment would be a slam dunk.

James Cason, the acting Deputy Secretary for the Department of the Interior, stressed in a May 12 letter that changes in Washington would not impact the tribe’s revenue sharing agreement with Connecticut.

“In practice, the Department has not disturbed long-standing compacts when reviewing amendments to the underlying agreement,” Cason wrote. “Here, the Tribes and the State have long-relied upon the Compacts that have facilitated a significant source of revenue for the Tribes and the State. The Department does not anticipate disturbing these underlying agreements.”

Rep. Joe Verrengia, chairman of the Public Safety and Security Committee, said Tuesday that they are waiting for an opinion from Jepsen, but he doesn’t believe they can “go forward without making changes to the law which would require it to come back to the legislature for a vote,”

He said the BIA letter is not a rubber stamp approval and it’s his opinion that any changes would have to come back to the General Assembly for approval.

But approval for East Windsor may not be as easy as it was in June.

“It may be problematic in moving forward because the political landscape has changed, those who voted in favor—the Bridgeport and New Haven delegations—carried the day in the approving the East Windsor casino.”

MGM’s announcement Monday of a Bridgeport casino, which includes a partnership with New Haven, may make it harder for lawmakers from Bridgeport and New Haven to offer their support.

At an unrelated press conference Monday, Gov. Dannel P. Malloy said he thinks MGM is adept at having as many cards on the table as possible.

“They admit in their own answers to questions earlier today that this would violate our agreement with the tribal nations so over the next two years that would have a negative impact to the tune of almost $500 million,” Malloy said. “I don’t think either the Democratic or Republican budget reflected the ability to handle almost $500 million in lost revenue over the next two years.”

Malloy is referring to the slot revenue that the two tribes pay the state under the currently gaming agreements. They had sought the BIA’s approval to amend the contract to add a revenue sharing agreement for the East Windsor facility.

MGM lobbied Connecticut lawmakers to open up the bidding process for a third casino and instead the General Assembly voted in favor of legislation to allow the tribes to build a casino in East Windsor.

It’s unclear now though how quickly the tribes will be able to move forward and break ground in East Windsor.

“The letter we received from the BIA affirms two points: 1) that both tribes maintain their exclusivity in the state and 2) that it’s up to that state and the tribes to agree that the exclusivity provisions will not be breached by their arrangement to jointly own and operate the East Windsor facility,” Andrew Doba, a spokesman for MMCT the joint tribal entity. “We view last year’s massive, bipartisan vote in favor of the project as positive proof that our state’s leaders understand exactly what’s at stake.”

He said the facts remain that “If we don’t build a casino in East Windsor, 9,000 Connecticut residents are going to lose their jobs and the state will lose hundreds of millions of dollars in revenue.”