The government loans would offer the Crow a chance to reclaim lands stripped from the tribe or sold to outsiders over the last 140 years. Tribal Chairman Carl Venne said the Crow want to manage their homeland themselves.

But Indian Affairs Director Jerold Gidner told a Senate panel in Washington Thursday that his agency is concerned about the size of the loans. He also said it was unclear who would determine land prices and whether the program could meet a September 2012 deadline outlined in a bill before Congress.

The tribe owns less than a quarter of its 2.2 million acre reservation along the Montana-Wyoming border. The rest is owned by privately, including 700,000 acres by non-Indians.

A bill introduced last year by Montana's Democratic U.S. senators, Max Baucus and Jon Tester, would loan the tribe $380 million to purchase non-tribal land and put it into a trust. The land could then be put to use for agriculture or other purposes that would generate tribal revenue.