A decision that threatens plans for the $1 billion First Light Casino & Resort in Taunton is being challenged by the Mashpee Wampanoag tribe and the U.S. Department of Interior.

On Thursday, both the Department of Justice and the Tribe filed separate notices of appeal in the First Circuit Court of Appeals in Boston challenging Judge William Young’s July ruling in the case of Littlefield v Department of the Interior. Judge Young ruled that the Department of the Interior lacked the authority to approve the Mashpee Wampanoag Tribe’s land-into-trust application last year placing more than 300 acres in Mashpee and Taunton into trust for the tribe.

In September 2015, the U.S. Department of the Interior approved a land into trust application submitted by the Mashpee Wampananog for land designated for their Project First Light Resort & Casino in the city of Taunton, Massachusetts. However, a group of local property owners opposed to the land grant and the casino and resort convinced a federal court judge that the Bureau of Indian Affairs (BIA) erred in its decision. The judge deemed that the tribe was not federally recognized at the time of the passing of the landmark 1934 Indian Reorganization Act. In October, Judge Young declined to reconsider his July verdict despite a direct appeal from the Department of Justice.

Judge Young’s summer decision would mean the Mashpee Wampanoag would have to prove that in 1934 the Tribe was under the control of the federal government. In a statement, the tribe’s Council Chairman Cedric Cromwell said, “This is a continuation of our fight to remain on the land our ancestors have lived on for thousands of years.”

According to the tribe’s statement, as the appeal progresses, whether or not the tribe is eligible to have its land held in trust under category 1, will be also be determined by federal officials. Category 1 would establish that the Mashpee Wampananog was “under federal jurisdiction” at the time the 1934 law was in effect. The September 2015 decision was based on “category 2,” meaning that the Tribe had been residing continuously on an existing reservation, under the IRA.

Also indicated in the tribal council chairman’s statement on December 9, a letter was sent last week to Mashpee tribal leaders by the BIA, stating that it was prepared to consider revising its initial Record-Of-Decision (ROD). Cromwell said he was confident the federal government will preserve the Tribe’s ancestral homeland. “The evidence that our Tribe was under federal jurisdiction in 1934 is compelling. I have no doubt that once all the evidence is reviewed, the Interior Department will issue a revised Record-Of-Decision,” said Cromwell.

The Mashpee Wampanoag, which was federally recognized in 2007, broke ground on its Taunton casino in April despite the challenges as to when it was first under federal jurisdiction. The city of Taunton became the tribe’s targeted location for a casino in 2012 after a 2011 state casino law authorized third and final resort casino license.