WASHINGTON (AP) - A federal judge ruled Thursday that American Indian plaintiffs are entitled to $455 million in a long-running trust case, a fraction of the $47 billion they wanted.

But U.S. District Judge James Robertson did not say how the government should award the money, writing that his opinion “leaves for another day the question of how and to whom the award should be distributed.”

Robertson's final number is close to government estimates and far from the billions sought by plaintiffs in the 12-year trial. The lawsuit ’Äî filed on behalf of a half-million American Indians and their heirs ’Äî claims they were swindled out of billions of dollars in oil, gas, grazing, timber and other royalties overseen by the Interior Department since 1887.

The judge said he will have to hold another proceeding to decide how the money will be awarded, hinting that he hopes for a settlement between the two parties before then.

“Perhaps it is not too much to hope that the announcement in this memorandum of a hard number will give rise to some off-line conversation between the parties in the meantime,” wrote Robertson, who is based in Washington, D.C.

At issue was how much of the royalty money was withheld from the Indian plaintiffs over the years, and whether it was held in the U.S. treasury at a benefit to the government.

Robertson said in the opinion that plaintiffs did not successfully argue that the money was of benefit to the government over the years, significantly reducing his final estimate of what the American Indians were owed.

“Plaintiffs' demonstrated willingness to accept data they liked and reject data they disliked did not enhance the credibility of their model,” he added.

In a statement, lead plaintiff Elouise Cobell, a Blackfeet Indian, said she is “disappointed, to say the least.”

“We believe we presented a strong, compelling case that individual Indian trust beneficiaries are entitled to much more than the government's admitted mismanagement of our trust monies over the past 120 years,” she said.

The Interior Department broke its customary silence on the case to praise the ruling.

“The department is gratified that the court recognized the complexities and uncertainties involved in this case,” said James E. Cason, associate deputy Secretary of the Interior.

Because many of the records have been lost or destroyed, it has been up to the court to decide how to best estimate how much the individual Indians - many of whom are nearing the end of their lives - should be paid.

During the course of the trial, plaintiffs reduced the amount they said they were owed based on documents that became available in the proceedings. They settled on $47 billion, down from their estimate going into the trial, which was $58 billion. Earlier estimates were as high as $100 billion.

The government proposed paying $7 billion partly to settle the Cobell lawsuit in March 2007, but that was rejected by the plaintiffs.

In a January decision, Robertson said the Interior Department had “unreasonably delayed” its accounting of the money owed to landholders and that the task was ultimately impossible. He called the June trial to consider whether money was owed, and, if so, how much was owed.

The class-action suit deals with individual Indians' lands and covers about 500,000 Indians and their heirs. Several tribes have sued separately, claiming mismanagement of their lands.

The case has dragged on for several years, with occasional fireworks.

U.S. District Judge Royce Lamberth ordered the department to disconnect its computers from the Internet for failing to provide adequate security for the Indians' trust records. He also held President Bush's interior secretary, Gale Norton, and her Clinton-era predecessor, Bruce Babbitt, in contempt for their handling of the trust fund.

Lamberth later was removed by the U.S. Court of Appeals for the District of Columbia Circuit, which said he had lost his objectivity. The government had asked that Lamberth be replaced after the judge lambasted the department, writing in a decision that it “is a dinosaur,” the morally and culturally oblivious hand-me-down of a disgracefully racist and imperialist government that should have been buried a century ago.”

Robertson, who took over, has made it clear he wants to be the last judge on the case.

“The Cobell case will no doubt stand, in some respects, as a cautionary tale about the limited ability of a court to right historical wrongs that could have been - and should have been - settled by the same political branches in recognition of their own failure to preserve the trust,” he wrote.