A judge has approved a nearly $1 billion settlement between the Obama administration and Native American tribes over claims the government shorted tribes for decades on contract costs to manage education, law enforcement and other federal services.

Attorneys for the tribes learned Wednesday that a federal judge in Albuquerque, New Mexico, approved the agreement, about five months after the Interior Department and tribal leaders announced they had reached a proposed $940 million settlement in the class-action lawsuit.

The judge's approval filed late Tuesday starts a process to release payment to the tribes that an attorney said could take several months. The ruling also authorized a $1.2 million reimbursement for lead plaintiff's costs, and an agreement for attorneys to receive 8.5 percent of the final settlement amount.

"The end result was there were no objections to the settlement and no objections to the fee request," said Michael Gross, an attorney for the tribes. "This showed a unity among Indian tribes that is absolutely astounding."

Nearly 700 tribes or tribal agencies are expected to claim compensation, with amounts ranging from an estimated $8,000 for some Alaska Native villages and communities elsewhere to $58 million for the Navajo Nation.

Some underfunded federal contracts in the case reportedly dated back to the 1970s, when a policy change allowed tribes to gain more oversight of federal programs meant to fulfill obligations established through treaties and other agreements.

Val Panteah, governor of Zuni Pueblo, described "a financial death spiral" that came as his government tried to offset losses from the contracts in New Mexico. Other tribal leaders described trying to stem losses from the underfunded contracts with painful budget cuts as they tried to meet critical needs in their communities.

The case was first filed in 1990 by the Ramah Navajo Chapter, a community of about 4,000 that became the case's lead plaintiff, along with the Oglala Sioux Tribe in South Dakota and Zuni Pueblo.

In 2012, the case went before the U.S. Supreme Court, which sided with the tribes and sent the case back to the lower courts before the Interior Department announced a proposed settlement in September.

Since the Supreme Court ruling, Congress has appropriated hundreds of millions of dollars to fully fund contract support costs for tribes.

The settlement is the latest in a recent string of major agreements between the Interior Department and tribes to resolve legal disputes that languished for years. In the largest agreement, the government agreed to pay out $3.4 billion to resolve claims over royalties owed to generations of individual landowners.

"It just shows the Obama administration has been working throughout two terms to stop litigating with tribes," said Kevin Washburn, who recently resigned from his post as Interior Department Assistant Secretary for Indian Affairs. "Now, even in the last year of the administration, they're getting this lengthy case settled."

The Associated Press