Kalispel Tribe of Indians sued the US government on Tuesday over its approval of a rival casino project proposed by the Spokane Tribe in Airway Heights, Washington.

Situated two miles west of Kalispel Tribe’s casino, the new project “will have a devastating impact on Northern Quest, which funds nearly all of the Kalispel Tribe’s government operations,” said the lawsuit filed in federal court.

Governor of Washington Jay Inslee approved the Spokane Tribe’s $400m project last summer, despite heavy opposition from civic leaders in the region. Whilst the Kalispel Tribe contend the Interior Department violated the Indian Gaming Regulatory Act, the Spokane Tribe argue that that the casino will help lift members out of poverty and provide thousands of jobs.

Moreover, in comments she made last November, Carol Evans, the Spokane Tribe’s chairwoman, seemed to acknowledge the Kalispel’s displeasure with the new casino without naming them directly.

“Our studies show there is definitely room for two casinos,” Evans said. “We believe in healthy competition.”

The Spokane Tribe’s future West Plains Casino could take a decade to complete. It will include a casino, a hotel, restaurants and an outdoor plaza, and marks only the second time an off-reservation casino has been approved in the Washington state; the first being the Kalispel’s successful Northern Quest.