GRANTS PASS, Ore. (AP) — Indian tribes can grow and sell marijuana on their lands as long as they follow the same federal conditions laid out for states that have legalized the drug, the U.S. Justice Department said Thursday.

Some advocates said the announcement could open new markets across the country and give rise to a rich new business on reservations, not unlike the advent of casino gambling. Others said it was too early to tell; many tribes oppose legalization, and only a handful of tribes have expressed any interest in the marijuana business.

Oregon U.S. Attorney Amanda Marshall said that the Justice Department policy addresses questions raised by tribes about how legalization of pot in states like Oregon, Washington and Colorado would apply to Indian lands.

"That's been the primary message tribes are getting to us as U.S. attorneys," Marshall said from Portland. "What will the U.S. as federal partners do to assist tribes in protecting our children and families, our tribal businesses, our tribal housing? How will you help us combat marijuana abuse in Indian Country when states are no longer there to partner with us?"